--TRY
SELECT
A.CameraID, A.CryptMode, A.CameraName, B.CameraID AS LeftCameraID
FROM
C001_Camera A , C002_Control B
where
B.CameraID=A.CameraID
and
(A.ControlerID IS NOT NULL AND A.ControlerID != '')
ORDER BY
CAST(A.CameraID as SIGNED INTEGER)
SELECT
A.CameraID, A.CryptMode, A.CameraName, B.CameraID AS LeftCameraID
FROM
C001_Camera A , C002_Control B
where
B.CameraID=A.CameraID
and
(A.ControlerID IS NOT NULL AND A.ControlerID != '')
ORDER BY
CAST(A.CameraID as SIGNED INTEGER)
-->
CAST(A.CameraID as INTEGER)
left join:返回“表名1”的全部行,对于“表名2”中,不满足on条件的记录用空值替换。
rigth join:返回“表名2”的全部行,对于“表名1”中,不满足on条件的记录用空值替换。
full join:返回两张表中的所有记录,对于不满足on条件一端的记录用空值替换。
inner jon:只返回两张表中都满足on条件的记录
inner join 右端输入与左端匹配时,左端及右端才被选取。