Trying to create a json_object containing json_array from mysql workbench.
The following statement results in "Error Code: 1242. Subquery returns more than 1 row":
SELECT JSON_OBJECT('id', id,
'username', username,
'email', email,
'firstname', firstname,
'lastname', lastname,
'password', password,
'created', created,
'class_codes', (select JSON_ARRAY('id', id, 'code', code, 'created', created, 'fk_teacher', fk_teacher) from class_codes where fk_teacher=teachers.id)) FROM teachers where teachers.id=18;
Not sure how to fix it.