I require an SQL query to suggest courses by checking completed courses, prerequisites, and schedule overlaps because my current joins return errors. Please advise the proper syntax.
SELECT ci.course_id, ci.course_name
FROM student_profiles AS sp
JOIN course_enrollments AS ce ON sp.id = ce.student_id
LEFT JOIN course_requirements AS cr ON ce.course_id = cr.course_ref
JOIN class_timings AS ct ON ct.course_ref = ce.course_id
WHERE sp.id = 1 AND ce.status = 'pending';
hey, try using subqueries for checking prereqs then inner joining with the timetable; sometimes flexible join orders help resolve errors. double chk your alias use and conditions, might be a misassigned alias causing overlap even though logic is right
I faced a similar challenge when trying to implement a system that checked both course prerequisites and schedule conflicts. In my experience, breaking down the query into smaller subqueries that separately handle prerequisites and then the schedule check often simplifies troubleshooting. This makes it easier to identify exactly where the error is occurring. You may also want to verify that each alias is correctly assigned and that fields being compared are compatible data types. Sometimes rearranging the join order can also help narrow down the problem.
Hey everyone, I’ve been tinkering with a similar scenario and ended up leaning on Common Table Expressions (CTEs) to keep things neat. It really helped to break the query into manageable parts – one CTE to verify the prerequisites and another to check for schedule conflicts. That way, it’s a lot easier to debug when something goes off, and you can test each piece separately. Have any of you played around with CTEs for this kind of multi-step logic before? What strategies did you use to keep your queries organized? Would love to hear more about your approaches! 
hey, maybe try breaking your query into a couple of CTEs so you can isolate prereq checks and schedule overlaps separately. reordering joins and double chekcing datatypes might resolve hidden conflicts. hope this helps u fix it fast!