Mysql on delete set null

Update foreign key value in mysql

SET foreign_key_checks = 0;
UPDATE languages SET id='xyz' WHERE id='abc';
UPDATE categories_languages SET language_id='xyz' WHERE language_id='abc';
SET foreign_key_checks = 1;

Source: stackoverflow.com

How to delete the rows with null values in mysql

DELETE FROM user WHERE username IS NULL;

To Delete the Rows with the Null values if present in any specific Columns.

Mysql on delete set null

    FOREIGN KEY (child_col1, child_col2, ... child_col_n)
    REFERENCES parent_table (parent_col1, parent_col2, ... parent_col_n)
    ON DELETE SET NULL
    [ ON UPDATE { NO ACTION | CASCADE | SET NULL | SET DEFAULT } ]

Source: techonthenet.com

Similar codes

0 vote223 views1 answer
Show function mysql
SQL
5 votes221 views1 answer
Mysql get last day of month
SQL
1 vote257 views1 answer
Sql server if exists update else insert
SQL
2 votes238 views2 answers
How to DROP a table in mysql
SQL
0 vote292 views2 answers
Create more than 1 tables with references to each other in sqlite3
SQL
0 vote217 views1 answer
Postgresql import data from csv
SQL
0 vote182 views1 answer
Ms sql print more than 1 variable
SQL
7 votes216 views1 answer
Query delete duplicates
SQL
3 votes231 views3 answers
How to add month in update sql
SQL
2 votes243 views1 answer
Oracle apex who is connected
SQL