1, LEFT the JOIN Book on Anderson, d=b b.b ookId AND b.b ookSetId=# {bookSetId}

2, and LEFT the JOIN (SELECT * FROM Book WHERE bookSetId=# {bookSetId}) b on Anderson, d=b.b ookId

The two other SQL result is the same, the higher efficiency, beg god give directions!!!!!!!!!!!!!!!!

CodePudding user response:

1, run to see
2, enter SQL, press Ctrl + L in the manager to check the query plan