How to get the next auto-increment id in mysql - mysql

How to get the next id in mysql to insert it in the table
INSERT INTO payments (date, item, method, payment_code)
VALUES (NOW(), '1 Month', 'paypal', CONCAT("sahf4d2fdd45", id))

You can use
SELECT AUTO_INCREMENT
FROM information_schema.tables
WHERE table_name = 'table_name'
AND table_schema = DATABASE( ) ;
or if you do not wish to use information_schema you can use this
SHOW TABLE STATUS LIKE 'table_name'

You can get the next auto-increment value by doing:
SHOW TABLE STATUS FROM tablename LIKE Auto_increment
/*or*/
SELECT `auto_increment` FROM INFORMATION_SCHEMA.TABLES
WHERE table_name = 'tablename'
Note that you should not use this to alter the table, use an auto_increment column to do that automatically instead.
The problem is that last_insert_id() is retrospective and can thus be guaranteed within the current connection.
This baby is prospective and is therefore not unique per connection and cannot be relied upon.
Only in a single connection database would it work, but single connection databases today have a habit of becoming multiple connection databases tomorrow.
See: SHOW TABLE STATUS

This will return auto increment value for the MySQL database and I didn't check with other databases. Please note that if you are using any other database, the query syntax may be different.
SELECT AUTO_INCREMENT
FROM information_schema.tables
WHERE table_name = 'your_table_name'
and table_schema = 'your_database_name';
SELECT AUTO_INCREMENT
FROM information_schema.tables
WHERE table_name = 'your_table_name'
and table_schema = database();

The top answer uses PHP MySQL_ for a solution, thought I would share an updated PHP MySQLi_ solution for achieving this. There is no error output in this exmaple!
$db = new mysqli('localhost', 'user', 'pass', 'database');
$sql = "SHOW TABLE STATUS LIKE 'table'";
$result=$db->query($sql);
$row = $result->fetch_assoc();
echo $row['Auto_increment'];
Kicks out the next Auto increment coming up in a table.

In PHP you can try this:
$query = mysql_query("SELECT MAX(id) FROM `your_table_name`");
$results = mysql_fetch_array($query);
$cur_auto_id = $results['MAX(id)'] + 1;
OR
$result = mysql_query("SHOW TABLE STATUS WHERE `Name` = 'your_table_name'");
$data = mysql_fetch_assoc($result);
$next_increment = $data['Auto_increment'];

Use LAST_INSERT_ID() from your SQL query.
Or
You can also use mysql_insert_id() to get it using PHP.

Solution:
CREATE TRIGGER `IdTrigger` BEFORE INSERT ON `payments`
FOR EACH ROW
BEGIN
SELECT AUTO_INCREMENT Into #xId
FROM information_schema.tables
WHERE
Table_SCHEMA ="DataBaseName" AND
table_name = "payments";
SET NEW.`payment_code` = CONCAT("sahf4d2fdd45",#xId);
END;
"DataBaseName" is the name of our Data Base

Simple query would do
SHOW TABLE STATUS LIKE 'table_name'

For MySQL 8 use SHOW CREATE TABLE to retrieve the next autoincrement insert id:
SHOW CREATE TABLE mysql.time_zone
Result:
CREATE TABLE `time_zone` (
`Time_zone_id` int unsigned NOT NULL AUTO_INCREMENT,
`Use_leap_seconds` enum('Y','N') CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL DEFAULT 'N',
PRIMARY KEY (`Time_zone_id`)
) ENGINE=InnoDB AUTO_INCREMENT=1784 DEFAULT CHARSET=utf8 STATS_PERSISTENT=0 ROW_FORMAT=DYNAMIC COMMENT='Time zones'
See the AUTO_INCREMENT=1784 at the last line of returned query.
Compare with the last value inserted:
select max(Time_zone_id) from mysql.time_zone
Result:
+-------------------+
| max(Time_zone_id) |
+-------------------+
| 1783 |
+-------------------+
Tested on MySQL v8.0.20.

SELECT id FROM `table` ORDER BY id DESC LIMIT 1
Although I doubt in its productiveness but it's 100% reliable

You have to connect to MySQL and select a database before you can do this
$table_name = "myTable";
$query = mysql_query("SHOW TABLE STATUS WHERE name='$table_name'");
$row = mysql_fetch_array($query);
$next_inc_value = $row["AUTO_INCREMENT"];

I suggest to rethink what you are doing. I never experienced one single use case where that special knowledge is required. The next id is a very special implementation detail and I wouldn't count on getting it is ACID safe.
Make one simple transaction which updates your inserted row with the last id:
BEGIN;
INSERT INTO payments (date, item, method)
VALUES (NOW(), '1 Month', 'paypal');
UPDATE payments SET payment_code = CONCAT("sahf4d2fdd45", LAST_INSERT_ID())
WHERE id = LAST_INSERT_ID();
COMMIT;

You can't use the ID while inserting, neither do you need it. MySQL does not even know the ID when you are inserting that record. You could just save "sahf4d2fdd45" in the payment_code table and use id and payment_code later on.
If you really need your payment_code to have the ID in it then UPDATE the row after the insert to add the ID.

What do you need the next incremental ID for?
MySQL only allows one auto-increment field per table and it must also be the primary key to guarantee uniqueness.
Note that when you get the next insert ID it may not be available when you use it since the value you have is only within the scope of that transaction. Therefore depending on the load on your database, that value may be already used by the time the next request comes in.
I would suggest that you review your design to ensure that you do not need to know which auto-increment value to assign next

use "mysql_insert_id()". mysql_insert_id() acts on the last performed query, be sure to call mysql_insert_id() immediately after the query that generates the value.
Below are the example of use:
<?php
$link = mysql_connect('localhost', 'username', 'password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db('mydb');
mysql_query("INSERT INTO mytable VALUES('','value')");
printf("Last inserted record has id %d\n", mysql_insert_id());
?>
I hope above example is useful.

If return no correct AUTO_INCREMENT, try it:
ANALYZE TABLE `my_table`;
SELECT AUTO_INCREMENT FROM information_schema.TABLES WHERE (TABLE_NAME = 'my_table');
This clear cache for table, in BD

using the answer of ravi404:
CREATE FUNCTION `getAutoincrementalNextVal`(`TableName` VARCHAR(50))
RETURNS BIGINT
LANGUAGE SQL
NOT DETERMINISTIC
CONTAINS SQL
SQL SECURITY DEFINER
COMMENT ''
BEGIN
DECLARE Value BIGINT;
SELECT
AUTO_INCREMENT INTO Value
FROM
information_schema.tables
WHERE
table_name = TableName AND
table_schema = DATABASE();
RETURN Value;
END
using in your insert query, to create a SHA1 Hash. ex.:
INSERT INTO
document (Code, Title, Body)
VALUES (
sha1( getAutoincrementalNextval ('document') ),
'Title',
'Body'
);

Improvement of #ravi404, in case your autoincrement offset IS NOT 1 :
SELECT (`auto_increment`-1) + IFNULL(##auto_increment_offset,1)
FROM INFORMATION_SCHEMA.TABLES
WHERE table_name = your_table_name
AND table_schema = DATABASE( );
(auto_increment-1) : db engine seems to alwaus consider an offset of 1. So you need to ditch this assumption, then add the optional value of ##auto_increment_offset, or default to 1 : IFNULL(##auto_increment_offset,1)

For me it works, and looks simple:
$auto_inc_db = mysql_query("SELECT * FROM my_table_name ORDER BY id ASC ");
while($auto_inc_result = mysql_fetch_array($auto_inc_db))
{
$last_id = $auto_inc_result['id'];
}
$next_id = ($last_id+1);
echo $next_id;//this is the new id, if auto increment is on

SELECT AUTO_INCREMENT AS next_id FROM information_schema.tables WHERE table_name = 'table name' AND table_schema = 'database name of table name'

mysql_insert_id();
That's it :)

Related

mysql multiple update and insert query at once [duplicate]

I know that you can insert multiple rows at once, is there a way to update multiple rows at once (as in, in one query) in MySQL?
Edit:
For example I have the following
Name id Col1 Col2
Row1 1 6 1
Row2 2 2 3
Row3 3 9 5
Row4 4 16 8
I want to combine all the following Updates into one query
UPDATE table SET Col1 = 1 WHERE id = 1;
UPDATE table SET Col1 = 2 WHERE id = 2;
UPDATE table SET Col2 = 3 WHERE id = 3;
UPDATE table SET Col1 = 10 WHERE id = 4;
UPDATE table SET Col2 = 12 WHERE id = 4;
Yes, that's possible - you can use INSERT ... ON DUPLICATE KEY UPDATE.
Using your example:
INSERT INTO table (id,Col1,Col2) VALUES (1,1,1),(2,2,3),(3,9,3),(4,10,12)
ON DUPLICATE KEY UPDATE Col1=VALUES(Col1),Col2=VALUES(Col2);
Since you have dynamic values, you need to use an IF or CASE for the columns to be updated. It gets kinda ugly, but it should work.
Using your example, you could do it like:
UPDATE table SET Col1 = CASE id
WHEN 1 THEN 1
WHEN 2 THEN 2
WHEN 4 THEN 10
ELSE Col1
END,
Col2 = CASE id
WHEN 3 THEN 3
WHEN 4 THEN 12
ELSE Col2
END
WHERE id IN (1, 2, 3, 4);
The question is old, yet I'd like to extend the topic with another answer.
My point is, the easiest way to achieve it is just to wrap multiple queries with a transaction. The accepted answer INSERT ... ON DUPLICATE KEY UPDATE is a nice hack, but one should be aware of its drawbacks and limitations:
As being said, if you happen to launch the query with rows whose primary keys don't exist in the table, the query inserts new "half-baked" records. Probably it's not what you want
If you have a table with a not null field without default value and don't want to touch this field in the query, you'll get "Field 'fieldname' doesn't have a default value" MySQL warning even if you don't insert a single row at all. It will get you into trouble, if you decide to be strict and turn mysql warnings into runtime exceptions in your app.
I made some performance tests for three of suggested variants, including the INSERT ... ON DUPLICATE KEY UPDATE variant, a variant with "case / when / then" clause and a naive approach with transaction. You may get the python code and results here. The overall conclusion is that the variant with case statement turns out to be twice as fast as two other variants, but it's quite hard to write correct and injection-safe code for it, so I personally stick to the simplest approach: using transactions.
Edit: Findings of Dakusan prove that my performance estimations are not quite valid. Please see this answer for another, more elaborate research.
Not sure why another useful option is not yet mentioned:
UPDATE my_table m
JOIN (
SELECT 1 as id, 10 as _col1, 20 as _col2
UNION ALL
SELECT 2, 5, 10
UNION ALL
SELECT 3, 15, 30
) vals ON m.id = vals.id
SET col1 = _col1, col2 = _col2;
All of the following applies to InnoDB.
I feel knowing the speeds of the 3 different methods is important.
There are 3 methods:
INSERT: INSERT with ON DUPLICATE KEY UPDATE
TRANSACTION: Where you do an update for each record within a transaction
CASE: In which you a case/when for each different record within an UPDATE
I just tested this, and the INSERT method was 6.7x faster for me than the TRANSACTION method. I tried on a set of both 3,000 and 30,000 rows.
The TRANSACTION method still has to run each individually query, which takes time, though it batches the results in memory, or something, while executing. The TRANSACTION method is also pretty expensive in both replication and query logs.
Even worse, the CASE method was 41.1x slower than the INSERT method w/ 30,000 records (6.1x slower than TRANSACTION). And 75x slower in MyISAM. INSERT and CASE methods broke even at ~1,000 records. Even at 100 records, the CASE method is BARELY faster.
So in general, I feel the INSERT method is both best and easiest to use. The queries are smaller and easier to read and only take up 1 query of action. This applies to both InnoDB and MyISAM.
Bonus stuff:
The solution for the INSERT non-default-field problem is to temporarily turn off the relevant SQL modes: SET SESSION sql_mode=REPLACE(REPLACE(##SESSION.sql_mode,"STRICT_TRANS_TABLES",""),"STRICT_ALL_TABLES",""). Make sure to save the sql_mode first if you plan on reverting it.
As for other comments I've seen that say the auto_increment goes up using the INSERT method, this does seem to be the case in InnoDB, but not MyISAM.
Code to run the tests is as follows. It also outputs .SQL files to remove php interpreter overhead
<?php
//Variables
$NumRows=30000;
//These 2 functions need to be filled in
function InitSQL()
{
}
function RunSQLQuery($Q)
{
}
//Run the 3 tests
InitSQL();
for($i=0;$i<3;$i++)
RunTest($i, $NumRows);
function RunTest($TestNum, $NumRows)
{
$TheQueries=Array();
$DoQuery=function($Query) use (&$TheQueries)
{
RunSQLQuery($Query);
$TheQueries[]=$Query;
};
$TableName='Test';
$DoQuery('DROP TABLE IF EXISTS '.$TableName);
$DoQuery('CREATE TABLE '.$TableName.' (i1 int NOT NULL AUTO_INCREMENT, i2 int NOT NULL, primary key (i1)) ENGINE=InnoDB');
$DoQuery('INSERT INTO '.$TableName.' (i2) VALUES ('.implode('), (', range(2, $NumRows+1)).')');
if($TestNum==0)
{
$TestName='Transaction';
$Start=microtime(true);
$DoQuery('START TRANSACTION');
for($i=1;$i<=$NumRows;$i++)
$DoQuery('UPDATE '.$TableName.' SET i2='.(($i+5)*1000).' WHERE i1='.$i);
$DoQuery('COMMIT');
}
if($TestNum==1)
{
$TestName='Insert';
$Query=Array();
for($i=1;$i<=$NumRows;$i++)
$Query[]=sprintf("(%d,%d)", $i, (($i+5)*1000));
$Start=microtime(true);
$DoQuery('INSERT INTO '.$TableName.' VALUES '.implode(', ', $Query).' ON DUPLICATE KEY UPDATE i2=VALUES(i2)');
}
if($TestNum==2)
{
$TestName='Case';
$Query=Array();
for($i=1;$i<=$NumRows;$i++)
$Query[]=sprintf('WHEN %d THEN %d', $i, (($i+5)*1000));
$Start=microtime(true);
$DoQuery("UPDATE $TableName SET i2=CASE i1\n".implode("\n", $Query)."\nEND\nWHERE i1 IN (".implode(',', range(1, $NumRows)).')');
}
print "$TestName: ".(microtime(true)-$Start)."<br>\n";
file_put_contents("./$TestName.sql", implode(";\n", $TheQueries).';');
}
UPDATE table1, table2 SET table1.col1='value', table2.col1='value' WHERE table1.col3='567' AND table2.col6='567'
This should work for ya.
There is a reference in the MySQL manual for multiple tables.
Use a temporary table
// Reorder items
function update_items_tempdb(&$items)
{
shuffle($items);
$table_name = uniqid('tmp_test_');
$sql = "CREATE TEMPORARY TABLE `$table_name` ("
." `id` int(10) unsigned NOT NULL AUTO_INCREMENT"
.", `position` int(10) unsigned NOT NULL"
.", PRIMARY KEY (`id`)"
.") ENGINE = MEMORY";
query($sql);
$i = 0;
$sql = '';
foreach ($items as &$item)
{
$item->position = $i++;
$sql .= ($sql ? ', ' : '')."({$item->id}, {$item->position})";
}
if ($sql)
{
query("INSERT INTO `$table_name` (id, position) VALUES $sql");
$sql = "UPDATE `test`, `$table_name` SET `test`.position = `$table_name`.position"
." WHERE `$table_name`.id = `test`.id";
query($sql);
}
query("DROP TABLE `$table_name`");
}
Why does no one mention multiple statements in one query?
In php, you use multi_query method of mysqli instance.
From the php manual
MySQL optionally allows having multiple statements in one statement string. Sending multiple statements at once reduces client-server round trips but requires special handling.
Here is the result comparing to other 3 methods in update 30,000 raw. Code can be found here which is based on answer from #Dakusan
Transaction: 5.5194580554962
Insert: 0.20669293403625
Case: 16.474853992462
Multi: 0.0412278175354
As you can see, multiple statements query is more efficient than the highest answer.
If you get error message like this:
PHP Warning: Error while sending SET_OPTION packet
You may need to increase the max_allowed_packet in mysql config file which in my machine is /etc/mysql/my.cnf and then restart mysqld.
There is a setting you can alter called 'multi statement' that disables MySQL's 'safety mechanism' implemented to prevent (more than one) injection command. Typical to MySQL's 'brilliant' implementation, it also prevents user from doing efficient queries.
Here (http://dev.mysql.com/doc/refman/5.1/en/mysql-set-server-option.html) is some info on the C implementation of the setting.
If you're using PHP, you can use mysqli to do multi statements (I think php has shipped with mysqli for a while now)
$con = new mysqli('localhost','user1','password','my_database');
$query = "Update MyTable SET col1='some value' WHERE id=1 LIMIT 1;";
$query .= "UPDATE MyTable SET col1='other value' WHERE id=2 LIMIT 1;";
//etc
$con->multi_query($query);
$con->close();
Hope that helps.
You can alias the same table to give you the id's you want to insert by (if you are doing a row-by-row update:
UPDATE table1 tab1, table1 tab2 -- alias references the same table
SET
col1 = 1
,col2 = 2
. . .
WHERE
tab1.id = tab2.id;
Additionally, It should seem obvious that you can also update from other tables as well. In this case, the update doubles as a "SELECT" statement, giving you the data from the table you are specifying. You are explicitly stating in your query the update values so, the second table is unaffected.
You may also be interested in using joins on updates, which is possible as well.
Update someTable Set someValue = 4 From someTable s Inner Join anotherTable a on s.id = a.id Where a.id = 4
-- Only updates someValue in someTable who has a foreign key on anotherTable with a value of 4.
Edit: If the values you are updating aren't coming from somewhere else in the database, you'll need to issue multiple update queries.
No-one has yet mentioned what for me would be a much easier way to do this - Use a SQL editor that allows you to execute multiple individual queries. This screenshot is from Sequel Ace, I'd assume that Sequel Pro and probably other editors have similar functionality. (This of course assumes you only need to run this as a one-off thing rather than as an integrated part of your app/site).
And now the easy way
update my_table m, -- let create a temp table with populated values
(select 1 as id, 20 as value union -- this part will be generated
select 2 as id, 30 as value union -- using a backend code
-- for loop
select N as id, X as value
) t
set m.value = t.value where t.id=m.id -- now update by join - quick
Yes ..it is possible using INSERT ON DUPLICATE KEY UPDATE sql statement..
syntax:
INSERT INTO table_name (a,b,c) VALUES (1,2,3),(4,5,6)
ON DUPLICATE KEY UPDATE a=VALUES(a),b=VALUES(b),c=VALUES(c)
use
REPLACE INTO`table` VALUES (`id`,`col1`,`col2`) VALUES
(1,6,1),(2,2,3),(3,9,5),(4,16,8);
Please note:
id has to be a primary unique key
if you use foreign keys to
reference the table, REPLACE deletes then inserts, so this might
cause an error
I took the answer from #newtover and extended it using the new json_table function in MySql 8. This allows you to create a stored procedure to handle the workload rather than building your own SQL text in code:
drop table if exists `test`;
create table `test` (
`Id` int,
`Number` int,
PRIMARY KEY (`Id`)
);
insert into test (Id, Number) values (1, 1), (2, 2);
DROP procedure IF EXISTS `Test`;
DELIMITER $$
CREATE PROCEDURE `Test`(
p_json json
)
BEGIN
update test s
join json_table(p_json, '$[*]' columns(`id` int path '$.id', `number` int path '$.number')) v
on s.Id=v.id set s.Number=v.number;
END$$
DELIMITER ;
call `Test`('[{"id": 1, "number": 10}, {"id": 2, "number": 20}]');
select * from test;
drop table if exists `test`;
It's a few ms slower than pure SQL but I'm happy to take the hit rather than generate the sql text in code. Not sure how performant it is with huge recordsets (the JSON object has a max size of 1Gb) but I use it all the time when updating 10k rows at a time.
The following will update all rows in one table
Update Table Set
Column1 = 'New Value'
The next one will update all rows where the value of Column2 is more than 5
Update Table Set
Column1 = 'New Value'
Where
Column2 > 5
There is all Unkwntech's example of updating more than one table
UPDATE table1, table2 SET
table1.col1 = 'value',
table2.col1 = 'value'
WHERE
table1.col3 = '567'
AND table2.col6='567'
UPDATE tableName SET col1='000' WHERE id='3' OR id='5'
This should achieve what you'r looking for. Just add more id's. I have tested it.
UPDATE `your_table` SET
`something` = IF(`id`="1","new_value1",`something`), `smth2` = IF(`id`="1", "nv1",`smth2`),
`something` = IF(`id`="2","new_value2",`something`), `smth2` = IF(`id`="2", "nv2",`smth2`),
`something` = IF(`id`="4","new_value3",`something`), `smth2` = IF(`id`="4", "nv3",`smth2`),
`something` = IF(`id`="6","new_value4",`something`), `smth2` = IF(`id`="6", "nv4",`smth2`),
`something` = IF(`id`="3","new_value5",`something`), `smth2` = IF(`id`="3", "nv5",`smth2`),
`something` = IF(`id`="5","new_value6",`something`), `smth2` = IF(`id`="5", "nv6",`smth2`)
// You just building it in php like
$q = 'UPDATE `your_table` SET ';
foreach($data as $dat){
$q .= '
`something` = IF(`id`="'.$dat->id.'","'.$dat->value.'",`something`),
`smth2` = IF(`id`="'.$dat->id.'", "'.$dat->value2.'",`smth2`),';
}
$q = substr($q,0,-1);
So you can update hole table with one query

Mysql Select row, update values and insert into another table

I have a temporary table with some rows:
$query = "CREATE TEMPORARY TABLE {$tn} (
`id` int(11) NOT NULL AUTO_INCREMENT,
`type` varchar(255) NOT NULL,
`title` varchar(255) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB";
I would like to select each row in this table, nulify id, update 'type' (for example) and insert whole selected row into another table (which has the same columns as this table).
I tried this but I am getting an error near SET ( You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'SET )
foreach ($ids as $id) {//this is each id in temp table
$query = "INSERT INTO $another_table
SELECT * FROM {$tn} WHERE id='$id'
SET id=NULL, type='foo'";
$result = $conn->query($query) or die(mysqli_error($conn));
}
I am not a PHP guru, but this is the syntax you should be following. You may select any number of constants you wish from a table.
INSERT INTO $another_table (id, type, title)
SELECT NULL, 'foo', title
FROM {$tn}
WHERE id = '$id';
This assumes that the other destination table uses the same name for its columns as your first table. If not, then you will have to change the first line of my query.
Note that you should ideally be using a prepared statement here.
If both your tables have the SAME amount of columns, with the same order, and you want to avoid listing each and every column, You could just copy the entry and updated the changed value within the same transaction:
START TRANSACTION;
INSERT INTO table2 SELECT * FROM table1 WHERE id = 57;
UPDATE table2 SET columnYouWantToChange="New Value" WHERE id = 57;
COMMIT;
But maybe you should OUTLINE, what you are trying to achieve? having 2 tables with identical columns "smells" like bad design. Maybe you'd better use the same table along with revision numbers of your data row?
Your SQL is not valid, You have an insert statement with a set statement in it.
All you need is a basic INSERT SELECT this is also no need for the for loop.
INSERT INTO $another_table (id, type, title)
SELECT id, 'foo', title
FROM {$tn}
You can do the set statement as an update after inserting all rows if that is easier to get you head around.
UPDATE $another_table SET id = NULL
https://dev.mysql.com/doc/refman/8.0/en/insert-select.html
FYI if you want SET many or all the columns from a table with the same column names this query run on information_schema will generate the most tedious part of the code for you:
select concat('target.', column_name ,' = ','source.', column_name ,', ') as line
from `columns`
where `columns`.table_name = 'target';

Can I find out the next auto_increment to be used?

Is it possible to find out what the next auto increment will be for my primary key without executing an INSERT INTO query? Some rows are deleted meaning that it's not as easy as just adding one to a SELECT MAX query on the PK. Many thanks.
If you really want to know next auto_increment value try SHOW TABLE STATUS returns next Auto_increment field, e.g.:
SHOW TABLE STATUS WHERE name = your_table_name;
or
SELECT Auto_increment
FROM information_schema.tables
WHERE table_schema = DATABASE() AND table_name = your_table_name
You can get the value by executing
SHOW TABLE STATUS WHERE Name = nameOfTableHere
and then retrieving the column 'Auto_Increment' from the result
Try the following:
SELECT Auto_increment
FROM information_schema.tables
WHERE table_name= 'tableName'
AND table_schema = DATABASE();
This is also possible:
(SELECT (SELECT your_primary_key FROM Your_Table ORDER BY your_primary_key DESC LIMIT 1)+1);

SELECT last id, without INSERT

I'm trying to retrieve the id of one table A to insert into another table B. I cannot use last_insert_id() as i have not inserted anything into A. Any ideas on how to do this nicely?
$n = mysql_query("SELECT max(id) FROM tablename"); doesn't seem to work, nor does
$n = mysql_query("SELECT max(id) FROM tablename GROUP BY id");
In MySQL, this does return the highest value from the id column:
SELECT MAX(id) FROM tablename;
However, this does not put that id into $n:
$n = mysql_query("SELECT max(id) FROM tablename");
To get the value, you need to do this:
$result = mysql_query("SELECT max(id) FROM tablename");
if (!$result) {
die('Could not query:' . mysql_error());
}
$id = mysql_result($result, 0, 'id');
If you want to get the last insert ID from A, and insert it into B, you can do it with one command:
INSERT INTO B (col) SELECT MAX(id) FROM A;
You could descendingly order the tabele by id and limit the number of results to one:
SELECT id FROM tablename ORDER BY id DESC LIMIT 1
BUT: ORDER BY rearranges the entire table for this request. So if you have a lot of data and you need to repeat this operation several times, I would not recommend this solution.
I have different solution:
SELECT AUTO_INCREMENT - 1 as CurrentId FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'dbname' AND TABLE_NAME = 'tablename'
You can get maximum column value and increment it:
InnoDB uses the following algorithm to
initialize the auto-increment counter
for a table t that contains an
AUTO_INCREMENT column named ai_col:
After a server startup, for the first
insert into a table t, InnoDB executes
the equivalent of this statement:
SELECT MAX(ai_col) FROM t FOR UPDATE;
InnoDB increments by one the value
retrieved by the statement and assigns
it to the column and to the
auto-increment counter for the table.
If the table is empty, InnoDB uses the
value 1.
Also you can use SHOW TABLE STATUS and its "Auto_increment" value.
I think to add timestamp to every record and get the latest. In this situation you can get any ids, pack rows and other ops.

Multiple Updates in MySQL

I know that you can insert multiple rows at once, is there a way to update multiple rows at once (as in, in one query) in MySQL?
Edit:
For example I have the following
Name id Col1 Col2
Row1 1 6 1
Row2 2 2 3
Row3 3 9 5
Row4 4 16 8
I want to combine all the following Updates into one query
UPDATE table SET Col1 = 1 WHERE id = 1;
UPDATE table SET Col1 = 2 WHERE id = 2;
UPDATE table SET Col2 = 3 WHERE id = 3;
UPDATE table SET Col1 = 10 WHERE id = 4;
UPDATE table SET Col2 = 12 WHERE id = 4;
Yes, that's possible - you can use INSERT ... ON DUPLICATE KEY UPDATE.
Using your example:
INSERT INTO table (id,Col1,Col2) VALUES (1,1,1),(2,2,3),(3,9,3),(4,10,12)
ON DUPLICATE KEY UPDATE Col1=VALUES(Col1),Col2=VALUES(Col2);
Since you have dynamic values, you need to use an IF or CASE for the columns to be updated. It gets kinda ugly, but it should work.
Using your example, you could do it like:
UPDATE table SET Col1 = CASE id
WHEN 1 THEN 1
WHEN 2 THEN 2
WHEN 4 THEN 10
ELSE Col1
END,
Col2 = CASE id
WHEN 3 THEN 3
WHEN 4 THEN 12
ELSE Col2
END
WHERE id IN (1, 2, 3, 4);
The question is old, yet I'd like to extend the topic with another answer.
My point is, the easiest way to achieve it is just to wrap multiple queries with a transaction. The accepted answer INSERT ... ON DUPLICATE KEY UPDATE is a nice hack, but one should be aware of its drawbacks and limitations:
As being said, if you happen to launch the query with rows whose primary keys don't exist in the table, the query inserts new "half-baked" records. Probably it's not what you want
If you have a table with a not null field without default value and don't want to touch this field in the query, you'll get "Field 'fieldname' doesn't have a default value" MySQL warning even if you don't insert a single row at all. It will get you into trouble, if you decide to be strict and turn mysql warnings into runtime exceptions in your app.
I made some performance tests for three of suggested variants, including the INSERT ... ON DUPLICATE KEY UPDATE variant, a variant with "case / when / then" clause and a naive approach with transaction. You may get the python code and results here. The overall conclusion is that the variant with case statement turns out to be twice as fast as two other variants, but it's quite hard to write correct and injection-safe code for it, so I personally stick to the simplest approach: using transactions.
Edit: Findings of Dakusan prove that my performance estimations are not quite valid. Please see this answer for another, more elaborate research.
Not sure why another useful option is not yet mentioned:
UPDATE my_table m
JOIN (
SELECT 1 as id, 10 as _col1, 20 as _col2
UNION ALL
SELECT 2, 5, 10
UNION ALL
SELECT 3, 15, 30
) vals ON m.id = vals.id
SET col1 = _col1, col2 = _col2;
All of the following applies to InnoDB.
I feel knowing the speeds of the 3 different methods is important.
There are 3 methods:
INSERT: INSERT with ON DUPLICATE KEY UPDATE
TRANSACTION: Where you do an update for each record within a transaction
CASE: In which you a case/when for each different record within an UPDATE
I just tested this, and the INSERT method was 6.7x faster for me than the TRANSACTION method. I tried on a set of both 3,000 and 30,000 rows.
The TRANSACTION method still has to run each individually query, which takes time, though it batches the results in memory, or something, while executing. The TRANSACTION method is also pretty expensive in both replication and query logs.
Even worse, the CASE method was 41.1x slower than the INSERT method w/ 30,000 records (6.1x slower than TRANSACTION). And 75x slower in MyISAM. INSERT and CASE methods broke even at ~1,000 records. Even at 100 records, the CASE method is BARELY faster.
So in general, I feel the INSERT method is both best and easiest to use. The queries are smaller and easier to read and only take up 1 query of action. This applies to both InnoDB and MyISAM.
Bonus stuff:
The solution for the INSERT non-default-field problem is to temporarily turn off the relevant SQL modes: SET SESSION sql_mode=REPLACE(REPLACE(##SESSION.sql_mode,"STRICT_TRANS_TABLES",""),"STRICT_ALL_TABLES",""). Make sure to save the sql_mode first if you plan on reverting it.
As for other comments I've seen that say the auto_increment goes up using the INSERT method, this does seem to be the case in InnoDB, but not MyISAM.
Code to run the tests is as follows. It also outputs .SQL files to remove php interpreter overhead
<?php
//Variables
$NumRows=30000;
//These 2 functions need to be filled in
function InitSQL()
{
}
function RunSQLQuery($Q)
{
}
//Run the 3 tests
InitSQL();
for($i=0;$i<3;$i++)
RunTest($i, $NumRows);
function RunTest($TestNum, $NumRows)
{
$TheQueries=Array();
$DoQuery=function($Query) use (&$TheQueries)
{
RunSQLQuery($Query);
$TheQueries[]=$Query;
};
$TableName='Test';
$DoQuery('DROP TABLE IF EXISTS '.$TableName);
$DoQuery('CREATE TABLE '.$TableName.' (i1 int NOT NULL AUTO_INCREMENT, i2 int NOT NULL, primary key (i1)) ENGINE=InnoDB');
$DoQuery('INSERT INTO '.$TableName.' (i2) VALUES ('.implode('), (', range(2, $NumRows+1)).')');
if($TestNum==0)
{
$TestName='Transaction';
$Start=microtime(true);
$DoQuery('START TRANSACTION');
for($i=1;$i<=$NumRows;$i++)
$DoQuery('UPDATE '.$TableName.' SET i2='.(($i+5)*1000).' WHERE i1='.$i);
$DoQuery('COMMIT');
}
if($TestNum==1)
{
$TestName='Insert';
$Query=Array();
for($i=1;$i<=$NumRows;$i++)
$Query[]=sprintf("(%d,%d)", $i, (($i+5)*1000));
$Start=microtime(true);
$DoQuery('INSERT INTO '.$TableName.' VALUES '.implode(', ', $Query).' ON DUPLICATE KEY UPDATE i2=VALUES(i2)');
}
if($TestNum==2)
{
$TestName='Case';
$Query=Array();
for($i=1;$i<=$NumRows;$i++)
$Query[]=sprintf('WHEN %d THEN %d', $i, (($i+5)*1000));
$Start=microtime(true);
$DoQuery("UPDATE $TableName SET i2=CASE i1\n".implode("\n", $Query)."\nEND\nWHERE i1 IN (".implode(',', range(1, $NumRows)).')');
}
print "$TestName: ".(microtime(true)-$Start)."<br>\n";
file_put_contents("./$TestName.sql", implode(";\n", $TheQueries).';');
}
UPDATE table1, table2 SET table1.col1='value', table2.col1='value' WHERE table1.col3='567' AND table2.col6='567'
This should work for ya.
There is a reference in the MySQL manual for multiple tables.
Use a temporary table
// Reorder items
function update_items_tempdb(&$items)
{
shuffle($items);
$table_name = uniqid('tmp_test_');
$sql = "CREATE TEMPORARY TABLE `$table_name` ("
." `id` int(10) unsigned NOT NULL AUTO_INCREMENT"
.", `position` int(10) unsigned NOT NULL"
.", PRIMARY KEY (`id`)"
.") ENGINE = MEMORY";
query($sql);
$i = 0;
$sql = '';
foreach ($items as &$item)
{
$item->position = $i++;
$sql .= ($sql ? ', ' : '')."({$item->id}, {$item->position})";
}
if ($sql)
{
query("INSERT INTO `$table_name` (id, position) VALUES $sql");
$sql = "UPDATE `test`, `$table_name` SET `test`.position = `$table_name`.position"
." WHERE `$table_name`.id = `test`.id";
query($sql);
}
query("DROP TABLE `$table_name`");
}
Why does no one mention multiple statements in one query?
In php, you use multi_query method of mysqli instance.
From the php manual
MySQL optionally allows having multiple statements in one statement string. Sending multiple statements at once reduces client-server round trips but requires special handling.
Here is the result comparing to other 3 methods in update 30,000 raw. Code can be found here which is based on answer from #Dakusan
Transaction: 5.5194580554962
Insert: 0.20669293403625
Case: 16.474853992462
Multi: 0.0412278175354
As you can see, multiple statements query is more efficient than the highest answer.
If you get error message like this:
PHP Warning: Error while sending SET_OPTION packet
You may need to increase the max_allowed_packet in mysql config file which in my machine is /etc/mysql/my.cnf and then restart mysqld.
There is a setting you can alter called 'multi statement' that disables MySQL's 'safety mechanism' implemented to prevent (more than one) injection command. Typical to MySQL's 'brilliant' implementation, it also prevents user from doing efficient queries.
Here (http://dev.mysql.com/doc/refman/5.1/en/mysql-set-server-option.html) is some info on the C implementation of the setting.
If you're using PHP, you can use mysqli to do multi statements (I think php has shipped with mysqli for a while now)
$con = new mysqli('localhost','user1','password','my_database');
$query = "Update MyTable SET col1='some value' WHERE id=1 LIMIT 1;";
$query .= "UPDATE MyTable SET col1='other value' WHERE id=2 LIMIT 1;";
//etc
$con->multi_query($query);
$con->close();
Hope that helps.
You can alias the same table to give you the id's you want to insert by (if you are doing a row-by-row update:
UPDATE table1 tab1, table1 tab2 -- alias references the same table
SET
col1 = 1
,col2 = 2
. . .
WHERE
tab1.id = tab2.id;
Additionally, It should seem obvious that you can also update from other tables as well. In this case, the update doubles as a "SELECT" statement, giving you the data from the table you are specifying. You are explicitly stating in your query the update values so, the second table is unaffected.
You may also be interested in using joins on updates, which is possible as well.
Update someTable Set someValue = 4 From someTable s Inner Join anotherTable a on s.id = a.id Where a.id = 4
-- Only updates someValue in someTable who has a foreign key on anotherTable with a value of 4.
Edit: If the values you are updating aren't coming from somewhere else in the database, you'll need to issue multiple update queries.
No-one has yet mentioned what for me would be a much easier way to do this - Use a SQL editor that allows you to execute multiple individual queries. This screenshot is from Sequel Ace, I'd assume that Sequel Pro and probably other editors have similar functionality. (This of course assumes you only need to run this as a one-off thing rather than as an integrated part of your app/site).
And now the easy way
update my_table m, -- let create a temp table with populated values
(select 1 as id, 20 as value union -- this part will be generated
select 2 as id, 30 as value union -- using a backend code
-- for loop
select N as id, X as value
) t
set m.value = t.value where t.id=m.id -- now update by join - quick
Yes ..it is possible using INSERT ON DUPLICATE KEY UPDATE sql statement..
syntax:
INSERT INTO table_name (a,b,c) VALUES (1,2,3),(4,5,6)
ON DUPLICATE KEY UPDATE a=VALUES(a),b=VALUES(b),c=VALUES(c)
use
REPLACE INTO`table` VALUES (`id`,`col1`,`col2`) VALUES
(1,6,1),(2,2,3),(3,9,5),(4,16,8);
Please note:
id has to be a primary unique key
if you use foreign keys to
reference the table, REPLACE deletes then inserts, so this might
cause an error
I took the answer from #newtover and extended it using the new json_table function in MySql 8. This allows you to create a stored procedure to handle the workload rather than building your own SQL text in code:
drop table if exists `test`;
create table `test` (
`Id` int,
`Number` int,
PRIMARY KEY (`Id`)
);
insert into test (Id, Number) values (1, 1), (2, 2);
DROP procedure IF EXISTS `Test`;
DELIMITER $$
CREATE PROCEDURE `Test`(
p_json json
)
BEGIN
update test s
join json_table(p_json, '$[*]' columns(`id` int path '$.id', `number` int path '$.number')) v
on s.Id=v.id set s.Number=v.number;
END$$
DELIMITER ;
call `Test`('[{"id": 1, "number": 10}, {"id": 2, "number": 20}]');
select * from test;
drop table if exists `test`;
It's a few ms slower than pure SQL but I'm happy to take the hit rather than generate the sql text in code. Not sure how performant it is with huge recordsets (the JSON object has a max size of 1Gb) but I use it all the time when updating 10k rows at a time.
The following will update all rows in one table
Update Table Set
Column1 = 'New Value'
The next one will update all rows where the value of Column2 is more than 5
Update Table Set
Column1 = 'New Value'
Where
Column2 > 5
There is all Unkwntech's example of updating more than one table
UPDATE table1, table2 SET
table1.col1 = 'value',
table2.col1 = 'value'
WHERE
table1.col3 = '567'
AND table2.col6='567'
UPDATE tableName SET col1='000' WHERE id='3' OR id='5'
This should achieve what you'r looking for. Just add more id's. I have tested it.
UPDATE `your_table` SET
`something` = IF(`id`="1","new_value1",`something`), `smth2` = IF(`id`="1", "nv1",`smth2`),
`something` = IF(`id`="2","new_value2",`something`), `smth2` = IF(`id`="2", "nv2",`smth2`),
`something` = IF(`id`="4","new_value3",`something`), `smth2` = IF(`id`="4", "nv3",`smth2`),
`something` = IF(`id`="6","new_value4",`something`), `smth2` = IF(`id`="6", "nv4",`smth2`),
`something` = IF(`id`="3","new_value5",`something`), `smth2` = IF(`id`="3", "nv5",`smth2`),
`something` = IF(`id`="5","new_value6",`something`), `smth2` = IF(`id`="5", "nv6",`smth2`)
// You just building it in php like
$q = 'UPDATE `your_table` SET ';
foreach($data as $dat){
$q .= '
`something` = IF(`id`="'.$dat->id.'","'.$dat->value.'",`something`),
`smth2` = IF(`id`="'.$dat->id.'", "'.$dat->value2.'",`smth2`),';
}
$q = substr($q,0,-1);
So you can update hole table with one query