mysql - 如何为下面的脚本实现 Join 以避免嵌套脚本

Question

SELECT UserDCID AS UserDCCompForDelCount1
FROM CDICentral.dbo.UserDCComponent AS udc
WHERE(
    UserDCID IN(
        SELECT UserDCID FROM CDICentral.dbo.UserDC AS ud WHERE (
            UserID NOT IN(
                SELECT UserID FROM CVPLocal.dbo.CSWSecurity AS cs
            )
        )
    )
)

Answer 1

尝试这个 SQL 查询

SELECT UserDCID AS UserDCCompForDelCount1 
FROM CDICentral.dbo.UserDCComponent AS udc 
INNER JOIN CDICentral.dbo.UserDC AS ud ON udc.UserDCID=ud.UserDCID
INNER JOIN CVPLocal.dbo.CSWSecurity AS cs ON ud.UserDCID=cs.UserID