sql-server - SQL Server : ORDER BY in subquery with UNION

Question

我有两个查询与 UNION ALL¹ 组合在一起:

--Query 1
SELECT Flavor, Color
FROM Friends

 

--Query 2
SELECT Flavor,
    (SELECT TOP 1 Color
     FROM Rainbows
     WHERE Rainbows.StrangerID = Strangers.StrangerID
     ORDER BY Wavelength DESC
    ) AS Color
FROM Strangers

当然，两者单独工作都很好，但与 UNION ALL 结合使用时:

SELECT Flavor, Color
FROM Friends

UNION ALL

SELECT Flavor,
    (SELECT TOP 1 Color
     FROM Rainbows
     WHERE Rainbows.StrangerID = Strangers.StrangerID
     ORDER BY Wavelength DESC
    ) AS Color
FROM Strangers

查询失败并出现以下错误:

Msg 104, Level 15, State 1, Line 3
ORDER BY items must appear in the select list if the statement contains a UNION operator.

如何在带有 UNION ALL 的语句中使用 ORDER BY？

可复制粘贴示例

CREATE TABLE Friends (Flavor int, Color int)
CREATE TABLE Strangers (Flavor int, StrangerID int)
CREATE TABLE Rainbows (StrangerID int, Color int, Wavelength int)
go

SELECT Flavor, Color
FROM Friends

UNION ALL

SELECT Flavor,
    (SELECT TOP 1 Color
     FROM Rainbows
     WHERE Rainbows.StrangerID = Strangers.StrangerID
     ORDER BY Wavelength DESC
    ) AS Color
FROM Strangers
go

DROP TABLE Rainbows
DROP TABLE Strangers
DROP TABLE Friends

Server: Msg 104, Level 15, State 1, Line 2
ORDER BY items must appear in the select list if the statement contains a UNION operator.

脚注

• ¹精心设计的假设示例。或者不是。

另请参阅

• SQL Query - Using Order By in UNION
• SQL UNION and ORDER BY
• SQL: Using Top 1 in UNION query with Order By
• Impact of ordering of correlated subqueries within a projection

Answer 1

有点破解，但这会起作用。

CREATE TABLE Friends (Flavor int, Color int)
CREATE TABLE Strangers (Flavor int, StrangerID int)
CREATE TABLE Rainbows (StrangerID int, Color int, Wavelength int)
go

SELECT Flavor, Color
FROM Friends

UNION ALL

SELECT Flavor,
    (SELECT Color FROM 
        (SELECT TOP 1 Color, Wavelength
         FROM Rainbows
         WHERE Rainbows.StrangerID = Strangers.StrangerID
         ORDER BY Wavelength DESC
         ) AS Foo
    ) AS Color
FROM Strangers
go

DROP TABLE Rainbows
DROP TABLE Strangers
DROP TABLE Friends