thí dụ về LEFT JOIN, RIGHT JOIN trong SQL

**** Xoa trong Multichoise nhung mon khong thi nua

DELETE FROM MultiChoise WHERE
MultiChoise .MaMon IN (
SELECT  MultiChoise.MaMon
     FROM MultiChoise
     LEFT JOIN MonHoc
     ON MultiChoise .MaMon= MonHoc.MaMon
EXCEPT
     SELECT  MultiChoise.MaMon
     FROM MonHoc
     RIGHT JOIN MultiChoise
     ON MonHoc.MaMon= MultiChoise .MaMon where MonHoc.Monthi ='1')


**** Xoa bai thi co mon khong thi nua
****************************

DELETE FROM Baithi WHERE
Baithi.MaMon IN (
SELECT  Baithi.MaMon
     FROM Baithi
     LEFT JOIN MonHoc
     ON Baithi.MaMon= MonHoc.MaMon
EXCEPT
     SELECT  Baithi.MaMon
     FROM MonHoc
     RIGHT JOIN Baithi
     ON MonHoc.MaMon= Baithi.MaMon
    where MonHoc.Monthi ='1'  and LopMonID is not null)

thí dụ về LEFT JOIN, RIGHT JOIN trong SQL 2019-01-04T13:52:00+07:00 Rating: 4.5 Diposkan Oleh: http://pdunoteit.blogspot.com/