I have 2 tables 
Table child : sgl_id ,student_id,  school_id , state 
Table parent : sgl_id , school_id 
Im trying to update child.state = 1 but...
UPDATE child
SET state = 1
WHERE sgl_id 
IN (
SELECT child.sgl_id
FROM child
LEFT JOIN parent ON child.sgl_id = parent.sgl_id
 AND child.school_id = parent.school_id
WHERE 1
AND parent.sgl_id IS NULL )
