SELECT a.id, b.name
FROM a LEFT JOIN b ON a.id = b.id
If you get a NULL in the name field, you don't know if that's because there's no record in b for that id, or if there is a record in b for that id but it has a NULL name value. Sometimes that difference will be important.
SELECT a.id, b.name FROM a LEFT JOIN b ON a.id = b.id
If you get a NULL in the name field, you don't know if that's because there's no record in b for that id, or if there is a record in b for that id but it has a NULL name value. Sometimes that difference will be important.