How do I insert a sql row into a new table where it meets criteria but resets the id value. In other words, copy the row, but reset the id value.
This is my current sql
INSERT INTO followers_lost SELECT * FROM followers WHERE pk = $pk
I tried to SET id=null and VALUE (0), but both don't work.
All you have to do since you want all the columns except the identity is specify all the non-identity columns on the insert:
INSERT INTO [followers_lost] ([Column1],[column2]...{but not the identity
column})
SELECT [Column1],[column2]...{but not the identity column} FROM followers WHERE
pk = $pk
You can create the column and then update it:
SET #new_id=0;
UPDATE your_table
SET id = #new_id := #new_id + 1
where id = 0
OK based on your comment I think you are trying to take all or some of the fields from Followers except the PK and put them into Followers_Lost where they equal a certain PK. If you want multiple PK's you would need to change the where clause to an IN statement instead of an equal and adjust your values accordingly.
CREATE TABLE dbo.UAT_Followers_Lost (PK INT IDENTITY(1,1),DATA VARCHAR(50) )
CREATE TABLE dbo.UAT_Followers (PK INT IDENTITY(1,1),DATA VARCHAR(50) )
INSERT INTO dbo.UAT_Followers
(DATA)
SELECT 'Jan'
UNION ALL
SELECT 'Feb'
UNION ALL
SELECT 'Mar'
DECLARE #PK INT
SET #PK = 1
INSERT INTO dbo.UAT_Followers_Lost
(Data)
SELECT Data
FROM dbo.UAT_Followers
WHERE PK = #PK
Related
How to assign unique auto incrementing values to a certain column? Kind of like AUTO_INCREMENT does but it should be NULL at the time of insertion and assigned at some later point.
I have a table that gets regular data inserts and a few workers that process that data and set processed_at datetime field when they're done. Now I want incrementally select new processed rows since the last call. If I naively use where processed_at > #last_update_time I'm afraid there might be a situation where some records are processed at the same second and I miss some rows.
update: Can I just do
begin;
select #max := max(foo) from table1;
update table1 set foo = #max + 1 where id = 'bar' limit 1;
commit;
if foo column is indexed?
You can use a trigger to implement that.
CREATE TABLE my_increment (value INT, table_name TEXT);
INSERT INTO my_increment VALUES (0, 'your_table_name');
CREATE TRIGGER pk AFTER UPDATE ON your_table_name
BEGIN
UPDATE my_increment
SET value = value + 1
WHERE table_name = 'your_table_name';
UPDATE your_table_name
SET ID2 = (
SELECT value
FROM my_increment
WHERE table_name = 'your_table_name')
WHERE ROWID = new.ROWID;
END;
But bear in mind that this trigger will work on every execution of the Update query.
You can also do it manually:
Create the table to store increment value:
CREATE TABLE my_increment (value INT, table_name TEXT);
INSERT INTO my_increment VALUES (0, 'your_table_name');
Then when you want to update the table, get the last value from this table and insert value+1 to your column needed to be incremented.
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'm working on following query:
INSERT INTO a (id, value) VALUES (_id, (SELECT value FROM b WHERE b.id = _id));
Table a: id, value (has a default value)
Table b: id, value
Table b does not contain all requested values. So the SELECT query sometimes returns 0 rows. In this case it should use the default value of a.value.
Is this somehow possible?
Edit:
Solution for empty columns in comments of the post marked as solved.
you can wrap the value in coalesce(max(value), default_value)
INSERT INTO a (id, value)
VALUES (_id, (SELECT coalesce(max(value), default_value)) FROM b WHERE b.id = _id));
The following query would work. First the max(value) is looked up from table b for _id. It would be either NULL or equal to b.value. If it is NULL (checked using the COALESCE function), then the default value of the value column of table a is set as the value.
The default value of the value column of table a is accessed using the DEFAULT function (please refer Reference 1).
INSERT INTO a
SELECT
_id,
COALESCE(max(value), (SELECT DEFAULT(value) FROM a LIMIT 1)) value
FROM b
WHERE id = _id;
SQL Fiddle demo
Reference:
How to SELECT DEFAULT value of a field on SO
If MySQL follows other RDBMS behaviour, the default is only picked up when you don't even specify the field. This means that you need two different INSERT statements:
IF (EXISTS(SELECT * FROM b WHERE id = _id)) THEN
INSERT INTO a (id, value) SELECT _id, value FROM b WHERE id = _id;
ELSE
INSERT INTO a (id) SELECT _id;
END IF;
Or, possibly, something like this...
INSERT INTO a (id, value) SELECT _id, value FROM b WHERE id = _id;
IF ((SELECT ROW_COUNT()) = 0) THEN
INSERT INTO a (id) SELECT _id;
END IF;
Please note, this is conceptual. I've looked up the syntax for you, but I haven't tested it on MySQL.
I have an auto increment column ID, and for some situation I wanted the other column to be equal to the primary key + 1 value
ID | other
1 | 2
2 | 3
3 | 4
4 | 123 (some situation, it is not always plus 1)
How can I achieve this?
Here's what I have tried
INSERT INTO table (`ID`,`other`) VALUES ('',(SELECT MAX(ID)+1 FROM table))
But that returns an error
You can't specify target table 'table' for update in FROM clause
Try Below query:
ALTER TABLE dbo.table ADD
Column AS ([ID]+1)
GO
It will definitely work
Using a normal AUTO_INCREMENT column as id, I cannot think of a way to do this in MySQL. Triggers, which otherwise would have been an option, don't work well with AUTO_INCREMENT columns.
The only way I see is to do two commands for an INSERT;
INSERT INTO bop (value) VALUES ('These values should be 1 and 2');
UPDATE bop SET other = id+1 WHERE id = LAST_INSERT_ID();
An SQLfiddle to test with.
The closest I'm getting to what you're looking for is to generate sequences separately from AUTO_INCREMENT using a function, and use that instead to generate the table id;
DELIMITER //
CREATE TABLE bop (
id INT UNIQUE,
other INT,
value VARCHAR(64)
)//
CREATE TABLE bop_seq ( seq INT ) // -- Sequence table
INSERT INTO bop_seq VALUES (1) // -- Start value
CREATE FUNCTION bop_nextval() RETURNS int
BEGIN
SET #tmp = (SELECT seq FROM bop_seq FOR UPDATE);
UPDATE bop_seq SET seq = seq + 1;
RETURN #tmp;
END//
CREATE TRIGGER bop_auto BEFORE INSERT ON bop
FOR EACH ROW
SET NEW.id = bop_nextval(), NEW.other=NEW.id + 1;
//
That'd let you do inserts and have it autonumber like you want. The FOR UPDATE should keep the sequence transaction safe, but I've not load tested so you may want to do that.
Another SQLfiddle.
I solved this by updating 2 times the DB..
I wanted to do +1 from 19 till ..
UPDATE `table` SET `id`=`id`+101 WHERE id <= 19
UPDATE `table` SET `id`=`id`-100 WHERE id <= 119 AND id >= 101
I want to get rows of a table such that no column value is null. No hardcoding of column values. I have hundreds of column names so.
Output should be only row 2 since all that row has the values for all the columns. I do not want to specify all the column names for is not null. It should take it programmatically. Even if i add a new column it should work without changing the query. That is my vision.
I found something, but that means using CURSOR
DECLARE #ColumnName VARCHAR(200)
DECLARE #ColumnCount INT
DECLARE #sql VARCHAR(400)
CREATE TABLE #tempTable (Id INT)
DECLARE GetNonNullRows CURSOR
FOR
SELECT c.NAME, (SELECT COUNT(*) FROM sys.columns col WHERE col.object_id = c.OBJECT_ID) FROM sys.tables AS t
JOIN sys.columns AS c ON t.object_id = c.object_id
WHERE t.name = 'SomeTable' AND t.type = 'U'
OPEN GetNonNullRows
FETCH NEXT FROM GetNonNullRows INTO #ColumnName, #ColumnCount
WHILE ##FETCH_STATUS = 0
BEGIN
SET #sql = 'SELECT st.UniqueId FROM SomeTable AS st WHERE ' + CONVERT(varchar, #ColumnName) + ' IS NOT NULL'
INSERT INTO #tempTable
EXEC (#sql)
FETCH NEXT FROM GetNonNullRows INTO #ColumnName, #ColumnCount
END
CLOSE GetNonNullRows
DEALLOCATE GetNonNullRows
SELECT * FROM SomeTable AS st1
WHERE st1.UniqueId IN (SELECT Id FROM #tempTable AS tt
GROUP BY Id
HAVING COUNT(Id) = #ColumnCount)
DROP TABLE #tempTable
Let me to explain this a little.
First i create cursor which iterate through all the columns of one table. For each column, I've create sql script to search in table for not null values for selected column. For those rows that satisfies criteria, I take its unique ID and put in temp table, and this job I am using for all columns.
At the end only ID's which count is like columns count are your result set, because only rows that have identical number of appearances like number of columns in table may be rows with all non null values in all columns.
Try this ::
SELECT * FROM mytable WHERE column IS NOT NULL
try this
SELECT *
FROM your_table_name
where coalesce(column_1, column_2, column_3, ...., column_n) is not null
SQL alone cannot express such a concept.
You have to dinamically build the SQL query according to the table definition using some procedural language.
In Oracle you can use the dictionay view USER_TAB_COLUMNS to build the column list.
try using IS NOT NULL
SELECT * FROM table WHERE field_name IS NOT NULL
For more information, check out the mysql manual on working with null values.