Django migration sql for conditional triggers

Question

I want to create a trigger that only inserts into table when the condition is met. I\'ve tried using various combinations of IF/BEGIN/END and WHERE, but Django returns me an SQ

Answer 1

@variables are not DECLARED.

Either:

DECLARE user_same BOOLEAN;
SELECT 1 INTO user_same WHERE ...

or

SELECT @user_same := 1 WHERE ...

Better yet, this avoids the need for the variable.

IF (EXISTS SELECT * FROM ...)

Also, don't use the construct IN ( SELECT ... ); it is usually better to use WHERE EXISTS ( SELECT * FROM ... ) or JOIN ... ON ....

(There may be more problems after fixing those.)

Answer 2

Another easy way to do this.

You should add any symbols between ; delimiters for the appropriate converting MySQL syntax to the raw SQL.

CREATE TRIGGER trigger_name BEFORE INSERT ON table
FOR EACH ROW
BEGIN
IF NEW.number <> 'anynumber' AND NEW.number <> 'anynumber'
  THEN
    SET NEW.number = 'anynumber'; --
END IF; --
END

This example works due to the dash symbols.