sql - 检查另一个表sql中某列的值是否存在

Question

我是 SQL Server 的新手。
我必须将一列的值从表 A 复制到另一个表 B 相对于另一列(JOIN)
但在复制之前，我必须检查该值是否存在于另一个表 C 中。如果是，则复制，否则返回值不在表 C 中的记录。
我的查询是；

IF EXISTS (SELECT Branch_ID FROM ADM_Branch
INNER JOIN UBL$ on ADM_Branch.Branch_Code = UBL$.[Branch Code  ] 
 WHERE ADM_Branch.Branch_Code = [UBL$].[Branch Code] )

        UPDATE EMP_Personal
    SET Account_Number = UBL$.[Account ] , Bank_ID = 1 , Branch_ID = (select Branch_ID from ADM_Branch join UBL$ on ADM_Branch.Branch_Code = UBL$.[Branch Code  ] where EMP_Personal.Emp_ID = UBL$.[Employee ID  ])
    FROM EMP_Personal JOIN UBL$
    ON EMP_Personal.Emp_ID = UBL$.[Employee ID  ]


ELSE

    ( SELECT UBL$.[Employee ID  ],UBL$.[Name ],UBL$.[Account ],UBL$.[Branch Code  ]
    FROM UBL$) except ( SELECT UBL$.[Employee ID  ],UBL$.[Name ],UBL$.[Account ],UBL$.[Branch Code  ]
    FROM UBL$
    right join ADM_Branch on  ADM_Branch.Branch_Code = UBL$.[Branch Code  ])

Answer 1

我认为下面的代码会给你一些想法，我试图保持列名相同，但你可能需要做一些改变:

UPDATE EMP
SET EMP.Account_Number = UBL.[Account ],
    EMP.Bank_ID = 1,
    EMP.Branch_ID = ADM.Branch_ID   
FROM EMP_Personal EMP
JOIN UBL$ UBL ON EMP_Personal.Emp_ID = UBL.[Employee ID  ]
JOIN ADM_Branch ADM ON ADM.Branch_Code = UBL.[Branch Code  ];

SELECT [Employee ID  ],[Name ],[Account],[Branch Code  ]
FROM UBL$ 
WHERE [Branch Code  ] NOT IN (SELECT Branch_Code FROM ADM_Branch);