SQL：在一个存储过程中删除和插入

Question

我希望删除查询在开始时只执行一次。在执行插入语句之后，直到所有数据成功保存在数据库中。

Answer 1

尝试使用 MERGE 语句

-- 正确指定连接条件的 MERGE 语句。

USE tempdb;
GO
BEGIN TRAN;
MERGE Target AS T
USING Source AS S

ON (T.EmployeeID = S.EmployeeID) 
WHEN NOT MATCHED BY TARGET AND S.EmployeeName LIKE 'S%' 
    THEN INSERT(EmployeeID, EmployeeName) VALUES(S.EmployeeID, S.EmployeeName)
WHEN MATCHED 
    THEN UPDATE SET T.EmployeeName = S.EmployeeName
WHEN NOT MATCHED BY SOURCE AND T.EmployeeName LIKE 'S%'
    THEN DELETE 
OUTPUT $action, inserted.*, deleted.*;
ROLLBACK TRAN;
GO