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.)