sqlserver 行列转换（将列转换为行）

直接上语句

IF OBJECT_ID('tempdb.dbo.#Contact') IS NOT NULL DROP TABLE #Contact;
CREATE TABLE #Contact
(
    EmployeeID INT NOT NULL,
    PhoneNumber1 BIGINT,
    PhoneNumber2 BIGINT,
    PhoneNumber3 BIGINT
)
GO
INSERT #Contact
    (EmployeeID, PhoneNumber1, PhoneNumber2, PhoneNumber3)
VALUES (1, 2718353881, 3385531980, 5324571342),
        (2, 6007163571, 6875099415, 7756620787),
        (3, 9439250939, NULL, NULL);
SELECT EmployeeID,
    PhoneType,
    PhoneValue
FROM #Contact c
UNPIVOT
(
PhoneValue
FOR PhoneType IN ([PhoneNumber1], [PhoneNumber2], [PhoneNumber3])
) AS p;

创建的表全量查询

想要实现的结果

相当于下面语句的执行结果

SELECT EmployeeID,
    'PhoneNumber1' AS PhoneType,
    c.PhoneNumber1 AS PhoneValue
FROM #Contact c
WHERE c.PhoneNumber1 IS NOT NULL
UNION ALL
SELECT EmployeeID,
    'PhoneNumber2' AS PhoneType,
    c.PhoneNumber2 AS PhoneValue
FROM #Contact c
WHERE c.PhoneNumber2 IS NOT NULL
UNION ALL
SELECT EmployeeID,
    'PhoneNumber3' AS PhoneType,
    c.PhoneNumber3 AS PhoneValue
FROM #Contact c
WHERE c.PhoneNumber3 IS NOT NULL
ORDER BY EmployeeID, PhoneType;