Question

我有3个不同的数据库，每个数据库都包含表格我需要查询删除所有3个表中不存在的每个代码（主键）的行（不同数据库中的每个表）

类似的东西：

DELETE FROM dbA.tableX, dbB.tableY, dbC.tableZ
WHERE       dbA.tableX.column <> dbB.tableY.column <> dbC.tableZ.column;

在查询运行之后，所有表应具有相同数量的具有相同主键值的行。

Answer 1

由于您要从三个表中删除，因此您需要三个删除语句，但您可以将它们全部放在一个事务中。类似......

BEGIN TRANSACTION; 

WITH CTE AS 
 ( 
   SELECT * 
   FROM dbA.dbo.tableX X 
   INNER JOIN dbA.dbo.tableY Y ON X.Pk_Col = Y.Pk_Col
   INNER JOIN dbA.dbo.tableZ Z ON Z.Pk_Col = Y.Pk_Col
 ) 
 DELETE FROM dbA.dbo.tableX
 WHERE NOT EXISTS (SELECT 1 
                   FROM CTE 
                   WHERE dbA.dbo.tableX = C.Pk_Col) 

;WITH CTE AS 
 ( 
   SELECT * 
   FROM dbA.dbo.tableX X 
   INNER JOIN dbA.dbo.tableY Y ON X.Pk_Col = Y.Pk_Col
   INNER JOIN dbA.dbo.tableZ Z ON Z.Pk_Col = Y.Pk_Col
 ) 
 DELETE FROM dbA.dbo.tableY
 WHERE NOT EXISTS (SELECT 1 
                   FROM CTE 
                   WHERE dbA.dbo.tableX = C.Pk_Col) 

;WITH CTE AS 
 ( 
   SELECT * 
   FROM dbA.dbo.tableX X 
   INNER JOIN dbA.dbo.tableY Y ON X.Pk_Col = Y.Pk_Col
   INNER JOIN dbA.dbo.tableZ Z ON Z.Pk_Col = Y.Pk_Col
 ) 
 DELETE FROM dbA.dbo.tableZ
 WHERE NOT EXISTS (SELECT 1 
                   FROM CTE 
                   WHERE dbA.dbo.tableX = C.Pk_Col) 


COMMIT TRANSACTION;

Answer 2

我会简化M. Ali的答案，因为不需要从所有3个表中查询3次公共行。

    BEGIN TRANSACTION; 

    WITH CTE AS 
     ( 
       SELECT * 
       FROM dbA.dbo.tableX X 
       INNER JOIN dbA.dbo.tableY Y ON X.Pk_Col = Y.Pk_Col
       INNER JOIN dbA.dbo.tableZ Z ON Z.Pk_Col = Y.Pk_Col
     ) 
     DELETE FROM dbA.dbo.tableX
     WHERE NOT EXISTS (SELECT 1 
                       FROM CTE 
                       WHERE dbA.dbo.tableX = C.Pk_Col) 

        DELETE FROM dbA.dbo.tableY
     WHERE NOT EXISTS (SELECT 1 
                       FROM CTE 
                       WHERE dbA.dbo.tableX = C.Pk_Col) 

    DELETE FROM dbA.dbo.tableZ
     WHERE NOT EXISTS (SELECT 1 
                       FROM CTE 
                       WHERE dbA.dbo.tableX = C.Pk_Col) 


    COMMIT TRANSACTION;

在不同的数据库中删除没有相同代码的行

2 个答案: