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 vote195 views1 answer
Allow null in psql
SQL
0 vote185 views1 answer
Hw to delete a procedure in pl sql
SQL
4 votes180 views2 answers
Sql vs mysql
SQL
0 vote194 views1 answer
Sql multiple into
SQL
31 votes186 views3 answers
SQL Server change column data type
SQL
0 vote180 views1 answer
Add alternate add column sql
SQL
1 vote214 views2 answers
Sql split string by space
SQL
0 vote190 views1 answer
Unique element in sql
SQL
1 vote183 views2 answers
How to check if sql query is correct online
SQL
1 vote185 views1 answer
Mysql current time
SQL