SQL Server两表数据同步的多种方法详解

CREATE TABLE StudentA
(
    ID VARCHAR(32),
    Name VARCHAR(20),
    Sex VARCHAR(10)
)
GO
INSERT INTO StudentA (ID,Name,Sex)
SELECT '1001','张三','男'
UNION
SELECT '1002','李四','男'
UNION
SELECT '1003','王五','女'
GO
CREATE TABLE StudentB
(
    ID VARCHAR(32),
    Name VARCHAR(20),
    Sex VARCHAR(10)
)
GO
INSERT INTO StudentB (ID,Name,Sex)
SELECT '1001','张三','女'
UNION
SELECT '1002','李四','女'
UNION
SELECT '1003','王五','女'
UNION
SELECT '1004','赵六','女'

TRUNCATE TABLE dbo.StudentB
INSERT INTO dbo.StudentB SELECT * FROM dbo.StudentA

DELETE FROM dbo.StudentB WHERE NOT EXISTS (SELECT 1 FROM dbo.StudentA WHERE ID=dbo.StudentB.ID)
UPDATE B SET B.Name=A.Name,B.Sex=A.Sex
FROM dbo.StudentA A INNER JOIN dbo.StudentB B ON A.ID=B.ID
WHERE CHECKSUM(A.Name,A.Sex)<>CHECKSUM(B.Name,B.Sex)
INSERT INTO dbo.StudentB SELECT * FROM dbo.StudentA WHERE NOT EXISTS (SELECT 1 FROM dbo.StudentB WHERE ID=dbo.StudentA.ID)

MERGE INTO dbo.StudentB AS T USING dbo.StudentA AS S ON T.ID=S.ID
WHEN MATCHED THEN                --当ON条件成立时，更新数据。
    UPDATE SET T.Name=S.Name,T.Sex=S.Sex
WHEN NOT MATCHED THEN            --当源表数据不存在于目标表时，插入数据。
    INSERT VALUES (S.ID,S.Name,S.Sex)
WHEN NOT MATCHED BY SOURCE THEN  --当目标表数据不存在于源表时，删除数据。
    DELETE;