Hey everyone, I’m trying to figure out if MySQL supports complete outer joins. I’ve been working on a project and I need to combine data from two tables, including all the rows from both even if they don’t have matches. I know inner joins and left/right joins, but I’m not sure if MySQL has a built-in way to do a full outer join. Does anyone know if this is possible in MySQL? If it’s not directly supported, are there any workarounds or alternatives I should consider? I’d really appreciate any help or advice on this. Thanks in advance!
As someone who’s wrestled with this issue before, I can confirm MySQL doesn’t natively support full outer joins. However, there’s a workaround that’s served me well in similar situations. You can combine LEFT JOINs with UNION ALL and add a WHERE clause to filter out duplicates. Here’s a pattern I’ve used:
SELECT * FROM table1
LEFT JOIN table2 ON table1.id = table2.id
UNION ALL
SELECT * FROM table2
LEFT JOIN table1 ON table1.id = table2.id
WHERE table1.id IS NULL
This approach ensures you get all rows from both tables. The WHERE clause in the second part prevents duplication of matches. It’s not as elegant as a built-in FULL OUTER JOIN, but it gets the job done efficiently. Just remember to adjust the column names and join conditions to fit your specific tables.
hey lucasg, mysql doesn’t have a direct full outer join. But u can fake it with a UNION of LEFT JOINs. something like:
SELECT * FROM table1 LEFT JOIN table2 ON table1.id = table2.id
UNION
SELECT * FROM table2 LEFT JOIN table1 ON table1.id = table2.id
this should give u what ur looking for. hope it helps!