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 vote114 views4 answers
Mysql count table rows
SQL
0 vote120 views1 answer
Oracle table privileges
SQL
0 vote135 views1 answer
Postgresql inheritance
SQL
0 vote128 views1 answer
Mysql get only the field names in a table
SQL
2 votes204 views5 answers
Unique in sql server
SQL
0 vote119 views1 answer
Sql delete from with relation
SQL
0 vote108 views1 answer
Assign value to var in SQL
SQL
1 vote122 views2 answers
Oracle 18c xe ORA-65096
SQL
1 vote130 views2 answers
Sqlstate[hy000]: general error: 1005 can't create table (errno: 150 "foreign key constraint is incorrectly formed")
SQL
1 vote128 views1 answer
What is in condition in sql
SQL