Hoping someone can help me with a mysql query
Here’s what I have:
I table with a column “networkname” that contains data like this:
“VLAN-338-Network1-A,VLAN-364-Network2-A,VLAN-988-Network3-A,VLAN-1051-Network4-A”
I need a MySQL query that will update that column with only the vlan numbers in ascending order, stripping out everything else. ie.
“338, 364, 988, 1051”
Thanks,
David
In this script, I create a procedure to loop through the networkname values and parse out the numbers to a separate table, and then update YourTable using a group_concat function. This assumes your networkname values follow the 'VLAN-XXX' pattern in your example where 'XXX' is the 3-4 digit number you want to extract. This also assumes each record has a unique ID.
CREATE PROCEDURE networkname_parser()
BEGIN
-- load test data
drop table if exists YourTable;
create table YourTable
(
ID int not null auto_increment,
networkname nvarchar(100),
primary key (ID)
);
insert into YourTable(networkname) values
('VLAN-338-Network1-A,VLAN-364-Network2-A,VLAN-988-Network3-A,VLAN-1051-Network4-A'),
('VLAN-231-Network1-A,VLAN-4567-Network2-A'),
('VLAN-9876-Network1-A,VLAN-321-Network2-A,VLAN-1678-Network3-A');
-- add commas to the end of networkname for parsing
update YourTable set networkname = concat(networkname,',');
-- parse networkname into related table
drop table if exists ParseYourString;
create table ParseYourString(ID int,NetworkNumbers int);
while (select count(*) from YourTable where networkname like 'VLAN-%') > 0
do
insert into ParseYourString
select ID,replace(substr(networkname,6,4),'-','')
from YourTable
where networkname like 'VLAN-%';
update YourTable
set networkname = right(networkname,char_length(networkname)-instr(networkname,','))
where networkname like 'VLAN-%';
end while;
-- update YourTable.networkname with NetworkNumbers
update YourTable t
inner join (select ID,group_concat(networknumbers order by networknumbers asc) as networknumbers
from ParseYourString
group by ID) n
on n.ID = t.ID
set t.networkname = n.networknumbers;
END//
Call to procedure and select the results:
call networkname_parser();
select * from YourTable;
SQL Fiddle: http://www.sqlfiddle.com/#!2/01c77/1
Related
I have a lot of different tables in my database, and I need somehow to get last inserted rows from those tables. Like social networks feeds. Also, those tables are have not random, but unknown names, because they all generated by users.
In example:
I have tables: A,B,C and D with 5k rows in each table.
I need somehow to get last rows from those tables and make it ordered by id, like we do in a simple query: "SELECT * FROM table A ORDER BY id DESC", but I'm looking for something like: "SELECT * FROM A,B,C,D ORDER BY id DESC".
Tables have same structure.
You can use union and order by if your tables have the same structure. Something like:
select *
from (
select * from A
union all
select * from B
union all
select * from C
) order by id desc
If the tables don't have the same structure then you cannot select * from all and order them and you might want to do two queries. First would be:
select id, tableName
from (
select id, 'tableA' as tableName from A
union all
select id, 'tableB' as tableName from B
union all
select id, 'tableC' as tableName from C
) order by id desc
Which will give you the last IDs and the tables where they are inserted. And then you need to get the rows from each respective table.
With pure Mysql it will be a bit hard. You can select the table names like:
SELECT table_name FROM information_schema.tables; but still how to use them in the statement? You will need to generate it dynamically
A procedure to generate the query dynamically can be something like ( I haven't tested it but I believe with some debugging it should work) :
DELIMITER $$
CREATE PROCEDURE buildQuery (OUT v_query VARCHAR)
BEGIN
DECLARE v_finished INTEGER DEFAULT 0;
DECLARE v_table_count INTEGER DEFAULT 0;
DECLARE v_table varchar(100) DEFAULT "";
-- declare cursor for tables (this is for all tables but can be changed)
DEClARE table_cursor CURSOR FOR
SELECT table_name FROM information_schema.tables;
-- declare NOT FOUND handler
DECLARE CONTINUE HANDLER
FOR NOT FOUND SET v_finished = 1;
OPEN table_cursor;
SET v_query="select * from ( ";
get_table: LOOP
FETCH table_cursor INTO v_table;
SET v_table_count = v_table_count + 1;
IF v_finished = 1 THEN
LEAVE get_table;
END IF;
if v_table_count>1 THEN
CONCAT(vquery, " UNION ALL ")
END IF;
SET v_query = CONCAT(vquery," select * from ", v_table );
END LOOP get_table;
SET v_query = CONCAT(vquery," ) order by id desc " );
-- here v_query should be the created query with UNION_ALL
CLOSE table_cursor;
SELECT #v_query;
END$$
DELIMITER ;
If each table's id is counted seperatly you can't order by ID, so you'll need to calculate a global id and use it on all of your tables.
You can do it as follows:
Assuming you have 2 tables A,B:
Create Table A(id int NOT NULL auto_increment, name varchar(max), value varchar(max), PRIMARY_KEY(id));
Create Table B(id int NOT NULL auto_increment, name varchar(max), value varchar(max), PRIMARY_KEY(id));
Add another table IDS with id as auto increment primary key.
Create table IDS (id int NOT NULL auto_increment, ts Timestamp default CURRENT_TIMESTAMP, PRIMARY_KEY(id));
For all your tables id column should use now the id from the IDS table as foreign key instead of auto increment.
Create Table A(id int NOT NULL auto_increment, name varchar(max), value varchar(max), PRIMARY_KEY(id),CONSTRAINT fk_A_id FOREIGN KEY(id) REFERENCE IDS(id) ON DELETE CASCADE ON UPDATE CASCADE);
Create Table B(id int NOT NULL auto_increment, name varchar(max), value varchar(max), PRIMARY_KEY(id),CONSTRAINT fk_A_id FOREIGN KEY(id) REFERENCE IDS(id) ON DELETE CASCADE ON UPDATE CASCADE);
for each table add before insert trigger, the trigger should first insert row to the IDS table and insert the LAST_INSERT_ID the table.
Create TRIGGER befor_insert_A BEFORE INSERT On A
FOR EACH ROW
BEGIN
insert into IDS() values ();
set new.id = LAST_INSERT_ID();
END
Create TRIGGER befor_insert_B BEFORE INSERT On B
FOR EACH ROW
BEGIN
insert into IDS() values ();
set new.id = LAST_INSERT_ID();
END
Now you can create view from all tables with union all, the rows of v can be sorted now by the id and give the cronlogic order of insertion.
Create view V AS select * from A UNION ALL select * from B
For example you can query on V the latest 10 ids:
select * from V Order by id desc LIMIT 10
Other option is to add timestamp for each table and sort the view by the timestamp.
Hi are you looking for this? However the id is not a good column to see the last updated among different tables.
select *
from A
join B
on 1=1
join C
on 1=1
join D
on 1=1
order by A.id desc
I looked into MySQL duplicate key but cant figure it out.
I have a table like below:
id series chapter path(can be unique)
I want only insert data and not update. Lets say I have data like below:
seri:Naruto, klasor:567 ==> If both of these exist in table then do not insert.
seri:Naruto, klasor:568 ==> If Naruto exist but 568 does not exist then do insert.
How can I achieve this?
Easiest way would be to define unique index with two columns on that table:
ALTER TABLE yourtable ADD UNIQUE INDEX (seri,klasor);
You may also define two column primary key, which would work just as well.
Then use INSERT IGNORE to only add rows when they will not be duplicates:
INSERT IGNORE INTO yourtable (seri, klasor) VALUES ('Naruto',567);
INSERT IGNORE INTO yourtable (seri, klasor) VALUES ('Naruto',568);
Edit: As per comments, you can't use UNIQUE INDEX which complicates things.
SET #seri='Naruto';
SET #klasor=567;
INSERT INTO yourtable
SELECT seri,klasor FROM (SELECT #seri AS seri, #klasor AS klasor)
WHERE NOT EXISTS (SELECT seri, klasor FROM yourtable WHERE seri=#seri AND klasor=#klasor);
You may use the above query with two local variables or convert it to single statement by replacing the local variables with actual values.
Better way would be to use stored procedure:
CREATE PROCEDURE yourinsert (vseri VARCHAR(8), vklasor INT)
BEGIN
DECLARE i INT;
SELECT COUNT(*) INTO i FROM yourtable WHERE seri=vseri AND klasor=vklasor;
IF i=0 THEN
INSERT INTO yourtable (seri,klasor) VALUES (vseri, vklasor);
END IF;
END;
This would allow you to perform the INSERT using:
CALL yourinsert('Naruto',567);
INSERT INTO table_name (seri, klasor) VALUES ('Naruto',567)
WHERE NOT EXISTS( SELECT seri,klasor FROM table_name WEHERE seri='Naruto' AND klasor=567
)
Hope this helps..
I'm inserting some_data (a unique key column), and then using the resulting user_id (the primary key auto-increment column) in a separate statement (not shown)
INSERT IGNORE INTO users (some_data) VALUES ('test');
SELECT LAST_INSERT_ID(); <--- I do stuff with this.
But, of course, if some_data already exists (happens very frequently), LAST_INSERT_ID() returns 0. What is the best way to get the user_id based on the unique key some_data, in this case? Of course I can do a separate WHERE query, but not sure that is the most efficient.
From http://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html
INSERT INTO users ( id, some_col ) VALUES (n,some_val)
ON DUPLICATE KEY UPDATE id=LAST_INSERT_ID(id), some_col=some_val;
Not an ignore but might do the job?
Edit:
To be clear, this will update some_col with some_val and then set the LAST_INSERT_ID to return the id of the duplicate row.
It could just as well be this if you didn't want to update any data on the duplicate but just set the LAST_INSERT_ID() call to give you what you want:
INSERT INTO users ( user_name ) VALUES ( 'bobloblaw' )
ON DUPLICATE KEY UPDATE id=LAST_INSERT_ID( id );
Edit 2:
Use a proc to do the work and get back the id
DELIMITER $$
CREATE PROCEDURE insert_test( val1 varchar(10), val2 varchar(10) )
BEGIN
INSERT INTO test.test_table ( col1, col2 ) SELECT val1, val2 FROM ( select 1 ) as a
WHERE NOT EXISTS (
select 1 from test.test_table t where t.col1 = val1
);
SELECT id FROM test.test_table where col1 = val1;
END $$
DELIMITER ;
SELECT LAST_INSERT_ID() as id FROM table1
Why does this query sometimes return the last inserted id of another table other than table1?
I call it in Node.js (db-mysql plugin) and I can only do queries.
LAST_INSERT_ID() can only tell you the ID of the most recently auto-generated ID for that entire database connection, not for each individual table, which is also why the query should only read SELECT LAST_INSERT_ID() - without specifying a table.
As soon as you fire off another INSERT query on that connection, it gets overwritten. If you want the generated ID when you insert to some table, you must run SELECT LAST_INSERT_ID() immediately after doing that (or use some API function which does this for you).
If you want the newest ID currently in an arbitrary table, you have to do a SELECT MAX(id) on that table, where id is the name of your ID column. However, this is not necessarily the most recently generated ID, in case that row has been deleted, nor is it necessarily one generated from your connection, in case another connection manages to perform an INSERT between your own INSERT and your selection of the ID.
(For the record, your query actually returns N rows containing the most recently generated ID on that database connection, where N is the number of rows in table1.)
SELECT id FROM tableName ORDER BY id DESC LIMIT 1
I usually select the auto-incremented ID field, order by the field descending and limit results to 1. For example, in a wordpress database I can get the last ID of the wp_options table by doing:
SELECT option_id FROM wp_options ORDER BY option_id DESC LIMIT 1;
Hope that helps.
Edit - It may make sense to lock the table to avoid updates to the table which may result in an incorrect ID returned.
LOCK TABLES wp_options READ;
SELECT option_id FROM wp_options ORDER BY option_id DESC LIMIT 1;
Try this. This is working
select (auto_increment-1) as lastId
from information_schema.tables
where table_name = 'tableName'
and table_schema = 'dbName'
Most easy way:
select max(id) from table_name;
I only use auto_increment in MySQL or identity(1,1) in SQL Server if I know I'll never care about the generated id.
select last_insert_id() is the easy way out, but dangerous.
A way to handle correlative ids is to store them in a util table, something like:
create table correlatives(
last_correlative_used int not null,
table_identifier varchar(5) not null unique
);
You can also create a stored procedure to generate and return the next id of X table
drop procedure if exists next_correlative;
DELIMITER //
create procedure next_correlative(
in in_table_identifier varchar(5)
)
BEGIN
declare next_correlative int default 1;
select last_correlative_used+1 into next_correlative from correlatives where table_identifier = in_table_identifier;
update correlatives set last_correlative_used = next_correlative where table_identifier = in_table_identifier;
select next_correlative from dual;
END //
DELIMITER ;
To use it
call next_correlative('SALES');
This allows you to reserve ids before inserting a record. Sometimes you want to display the next id in a form before completing the insertion and helps to isolate it from other calls.
Here's a test script to mess around with:
create database testids;
use testids;
create table correlatives(
last_correlative_used int not null,
table_identifier varchar(5) not null unique
);
insert into correlatives values(1, 'SALES');
drop procedure if exists next_correlative;
DELIMITER //
create procedure next_correlative(
in in_table_identifier varchar(5)
)
BEGIN
declare next_correlative int default 1;
select last_correlative_used+1 into next_correlative from correlatives where table_identifier = in_table_identifier;
update correlatives set last_correlative_used = next_correlative where table_identifier = in_table_identifier;
select next_correlative from dual;
END //
DELIMITER ;
call next_correlative('SALES');
If you want to use these workarounds:
SELECT id FROM tableName ORDER BY id DESC LIMIT 1
SELECT MAX(id) FROM tableName
It's recommended to use a where clause after inserting rows. Without this you are going to have inconsistency issues.
in my table inv_id is auto increment
for my purpose this is worked
select `inv_id` from `tbl_invoice`ORDER BY `inv_id` DESC LIMIT 1;
I have a column that may contain entries like this:
abc.yahoo.com
efg.yshoo.com
hij.yahoo.com
I need to delete all the duplicates and LEAVE ONE ONLY as I don't need the others. Such command can be easily done if I know the second part (ex: yahoo.com) but my problem is that the part (yahoo.com) is not fixed. I may have entries such as:
abc.msn.com
efg.msn.com
hij.msn.com
And I want to treat all these cases at once. Is this possible?
To delete the duplicates you can use
DELETE FROM your_table t1
LEFT JOIN
(
SELECT MIN(id) AS id
FROM your_table
GROUP BY SUBSTRING_INDEX(REVERSE(col), '.', 2)
) t2 ON t2.id = t1.id
WHERE b.id IS NULL
If you need to create an UNIQUE constraint for that you can do the following
1.Add another field to hold the domain value
ALTER TABLE your_table ADD COLUMN `domain` VARCHAR(100) NOT NULL DEFAULT '';
2.Update it with the correct values
UPDATE your_table set domain = REVERSE(SUBSTRING_INDEX(REVERSE(col), '.', 2));
3.Add the unique constraint
ALTER IGNORE TABLE your_table ADD UNIQUE domain (domain);
4.Add before insert and before update trggers to set the domain column
DELIMITER $$
CREATE TRIGGER `your_trigger` BEFORE INSERT ON `your_table ` FOR EACH ROW
BEGIN
set new.domain = REVERSE(SUBSTRING_INDEX(REVERSE(new.col1), '.', 2));
END$$
CREATE TRIGGER `your_trigger` BEFORE UPDATE ON `your_table ` FOR EACH ROW
BEGIN
set new.domain = REVERSE(SUBSTRING_INDEX(REVERSE(new.col1), '.', 2));
END$$
DELIMITER ;
Note: this assumes the domain is the last 2 words when separated by '.', it will not work for a domain such as ebay.co.uk . For that you will probably need to make a stored function which returns the domain for a given host and use it instead of REVERSE(SUBSTRING_INDEX....
This is assuming that you just want to take out the letters before the first . then group on the column:
DELETE a FROM tbl a
LEFT JOIN
(
SELECT MIN(id) AS id
FROM tbl
GROUP BY SUBSTRING(column, LOCATE('.', column))
) b ON a.id = b.id
WHERE b.id IS NULL
Where id is your primary key column name, and column is the column that contains the values to group on.
This will also account for domains like xxx.co.uk where you have two parts at the end.
Make sure you have a backup of your current data or run this operation within a transaction (where you can ROLLBACK; if it didn't fit your needs).
EDIT: If after deleting the duplicates you want to replace the letters before the first . with *, you can simply use:
UPDATE tbl
SET column = CONCAT('*', SUBSTRING(column, LOCATE('.', column)))