|
Canada-ON-BURLINGTON Azienda Directories
|
Azienda News:
- MySQL DELETE FROM with subquery as condition - Stack Overflow
DELETE T FROM Target AS T RIGHT JOIN (full subquery already listed for the in() clause in answers above) ` AS TT ON (TT ID = T ID) And maybe it is answered in the "MySQL doesn't allow it", however, it is working fine for me PROVIDED I make sure to fully clarify what to delete (DELETE T FROM Target AS T)
- mysql - Foreign key constraints: When to use ON UPDATE and ON DELETE . . .
usually my default is: ON DELETE RESTRICT ON UPDATE CASCADE with some ON DELETE CASCADE for track tables (logs--not all logs--, things like that) and ON DELETE SET NULL when the master table is a 'simple attribute' for the table containing the foreign key, like a JOB table for the USER table Edit It's been a long time since I wrote that Now
- mysql - Getting Lock wait timeout exceeded; try restarting transaction . . .
HOW TO FORCE UNLOCK for locked tables in MySQL: Breaking locks like this may cause atomicity in the database to not be enforced on the sql statements that caused the lock This is hackish, and the proper solution is to fix your application that caused the locks
- How do I remove a MySQL database? - Stack Overflow
You can also find the location where that database is stored on windows, using xammp Find the location where the mysql data directory is And then delete it For example if your database is named logs, that might be at:E:\Program Files\xampp\mysql\data\logs –
- sql - delete all from table - Stack Overflow
Is a DDL(Data Definition Language), you can delete all data and clean identity If you want to use this, you need DDL privileges in table DDL statements example: CREATE, ALTER, DROP, TRUNCATE, etc DELETE FROM table_name DELETE FROM table_name WHERE 1=1 (is the same) Is a DML(Data Manipulation Language), you can delete all data DML
- MySQL foreign key constraints, cascade delete - Stack Overflow
If you delete the 'red' category, the only records that will cascade delete in categories_products are those where category_id = red It won't touch any records where 'category_id = blue', and it would not travel onwards to the "products" table, because there's no foreign key defined in that table
- How to delete a column from a table in MySQL - Stack Overflow
It is worth mentioning that MySQL 8 0 23 and above supports Invisible Columns CREATE TABLE tbl_Country( CountryId INT NOT NULL AUTO_INCREMENT, IsDeleted bit, PRIMARY KEY (CountryId) ); INSERT INTO tbl_Country VALUES (1, 1), (2,0); ALTER TABLE tbl_Country ALTER COLUMN IsDeleted SET INVISIBLE; SELECT * FROM tbl_Country; CountryId 1 2 ALTER TABLE tbl_Country DROP COLUMN IsDeleted;
- sql - How to delete from select in MySQL? - Stack Overflow
However, you can either SELECT then DELETE in separate queries, or nest another subquery and alias the inner subquery result (looks rather hacky, though): DELETE FROM posts WHERE id IN ( SELECT * FROM ( SELECT id FROM posts GROUP BY id HAVING ( COUNT(id) > 1 ) ) AS p )
- MySQL InnoDB not releasing disk space after deleting data rows from . . .
Therefore after delete data, run alter table that change nothing to release hardisk ( ie: table TBL_A has charset uf8, after delete data run ALTER TABLE TBL_A charset utf8 -> this command change nothing from your table but It makes mysql recreate your table and regain diskspace; Create TBL_B like TBL_A Insert select data you want to keep from
- sql - mysql delete under safe mode - Stack Overflow
SET SQL_SAFE_UPDATES = 0; DELETE FROM instructor WHERE salary BETWEEN 13000 AND 15000; SET SQL_SAFE_UPDATES = 1; If I'm honest, I can't say I've ever made a habit of running in safe mode Still, I'm not entirely comfortable with this answer since it just assumes you should go change your database config every time you run into a problem
|
|