Hi Arup, Am Sonntag, 22. September 2019, 15:30:38 CEST schrieb Arup Rakshit: > When someone adds a craftsmanship to their skill set, the contractor_skills > table holds that relationship. I don’t think distinct is the correct tool, > as it will eliminate the correct data. users and craftsmanship has m:n > relationship via the join table contractor_skills.
depending on the definition of table "contractor_skills" it can give you a n:m relationship between user_id and craftmanship_id, that is true. > SELECT > craftsmanships.id, > craftsmanships.name, > CASE WHEN contractor_skills.user_id IS NULL THEN > FALSE > ELSE > TRUE > END AS has > FROM > "craftsmanships" > LEFT JOIN "contractor_skills" ON "contractor_skills"."craftsmanship_id" = > "craftsmanships"."id" LEFT JOIN "users" ON "users"."id" = > "contractor_skills"."user_id" WHERE (contractor_skills.user_id = 8 > OR contractor_skills.user_id IS NULL) > ORDER BY > "craftsmanships"."id”; BUT: you don't use any of users' columns in select, where, or order by. And since users is in a left join it is just a table which is neither used nor relevant in that particular statement. In the end, it depends on how data is structured in your database and what you want to achieve. -- MfG Jan
