插入/更新/删除每一行SQL

Question

我在表TABLE1中有以下数据

SessionID
S1
S2
S3

我在另一个TABLE2中有以下数据

EmployeeID | Session
1          | NULL
2          | NULL
3          | NULL

我想要做的是更新/插入每一行示例

UPDATE table2 SET Session= (SELECT SessionID FROM TABLE1)
INSERT INTO( COPY each row and insert 2nd row session id from table1)

预期结果: TABLE2

EmployeeID | Session
1          | S1
2          | S1
3          | S1
1          | S2
2          | S2
3          | S2
1          | S3
2          | S3
3          | S3

任何洞察力都会有所帮助。

谢谢。

Answer 1

听起来好像您想在TABLE2中为当前TABLE2中的每一行和TABLE1中的每一行的每一种组合使用一行。如果是的话..。

BEGIN TRAN

SELECT * INTO #temp FROM TABLE2

DELETE TABLE2

INSERT TABLE2
(
    EmployeeID,
    Session
)
SELECT
    temp.EmployeeID,
    TABLE1.SessionID
FROM TABLE1 CROSS JOIN #temp temp

DROP #TEMP

COMMIT TRAN

Answer 2

我建议创建一个单独的Employee表。要将数据插入EmployeeSession (TABLE2)，请执行以下操作：

INSERT INTO EmployeeSession ( EmployeeID, SessionID )
    SELECT Employee.ID, [Session].ID
    FROM Employee, [Session]

Answer 3

我认为MERGE语句有帮助：

MERGE INTO TABLE2 t2
    USING (SELECT t2.EmployeeID, t1.SessionID
FROM TABLE2 t2
CROSS JOIN TABLE1 t1) t
        ON t2.EmployeeID = t.EmployeeID AND t2.Session = t.SessionID
    WHEN NOT MATCHED BY TARGET THEN
        INSERT (EmployeeID, Session) VALUES(t.EmployeeID, t.SessionID)
    WHEN NOT MATCHED BY SOURCE THEN
        DELETE
;