Question

I am trying to run a query that essentially looks like this:

INSERT INTO lessons_skills_xref (lessons_id, skills_id)
SELECT id FROM lessons, (SELECT id FROM skills WHERE title = "title 1")
/* PSEUDO CODE - Where the ids for both lesson and skill don't already exist */

Not sure how to accomplish the last part. Any ideas?

Answer 1

Assuming lessons_skills_xref has a unique key on (lessons_id,skills_id), an easy way would be to just use INSERT IGNORE

INSERT IGNORE INTO lessons_skills_xref (lessons_id, skills_id)
SELECT id, (SELECT id FROM skills WHERE title = "title 1") FROM lessons

The INSERT IGNORE syntax will insert the record if it doesn’t already exist, or ignore it if it’s already there.