使用带有 UNION 问题的 order by 子句答案

【问题标题】：Using order by clause with UNION issue使用带有 UNION 问题的 order by 子句
【发布时间】：2015-10-12 12:02:55
【问题描述】：

当我使用 UNION 使用 Order by 时出现以下错误。

“ORDER BY 子句在视图、内联函数、派生表、子查询和公用表表达式中无效，除非还指定了 TOP 或 FOR XML。”

declare @results table (hdate date, name varchar(100), id1 int)

insert into @results select cast('10-01-2015' as date), 'val1 1', 1
insert into @results select cast('10-02-2015' as date), 'val2 2', 2

insert into @results select cast('10-03-2015' as date), 'thanks 1', 3
insert into @results select cast('10-04-2015' as date), 'thanks 2', 3

select  (DATENAME(dw, hdate) + ', ' + 
        DATENAME(mm, hdate) + ' '  + 
      DATENAME(dd, hdate)) AS h_date, name AS h_name from @results where id1 in (1,2) 
order by id1
UNION
SELECT (STUFF((
        SELECT ', ' + (DATENAME(dw, hdate) + ', ' + 
       DATENAME(mm, hdate) + ' '  + 
       DATENAME(dd, hdate))
        FROM @results
        WHERE id1 = 3
        FOR XML PATH('')
        ), 1, 2, '')
    ) AS h_date, 'Giving Day' AS h_name

【问题讨论】：

标签： sql-server tsql

【解决方案1】：

您可以尝试以下方法：

declare @results table (hdate date, name varchar(100), id1 int)

insert into @results select cast('10-01-2015' as date), 'val1 1', 1
insert into @results select cast('10-02-2015' as date), 'val2 2', 2

insert into @results select cast('10-03-2015' as date), 'thanks 1', 3
insert into @results select cast('10-04-2015' as date), 'thanks 2', 3

SELECT  id1,
        (DATENAME(dw, hdate) + ', ' + 
        DATENAME(mm, hdate) + ' '  + 
        DATENAME(dd, hdate)) AS h_date, name AS h_name from @results where id1 in (1,2) 

UNION

SELECT DISTINCT id1,(STUFF((
        SELECT ', ' + (DATENAME(dw, hdate) + ', ' + 
               DATENAME(mm, hdate) + ' '  + 
               DATENAME(dd, hdate))
        FROM @results r2
        WHERE  r1.id1 = r2.id1
        FOR XML PATH('')
        ), 1, 2, '')
    ) AS h_date, 'Giving Day' AS h_name
FROM @results r1
WHERE id1 = 3 
ORDER BY id1

【讨论】：

【解决方案2】：

正如错误所示，您不能将 ORDER BY 与 UNION 一起使用。因此，您必须在订购之前将其包装在子查询中：

select h_date, h_name from (
select  (DATENAME(dw, hdate) + ', ' + 
        DATENAME(mm, hdate) + ' '  + 
      DATENAME(dd, hdate)) AS h_date, name AS h_name 
      , id1
      from @results 
      where id1 in (1,2) 
UNION
SELECT (STUFF((
        SELECT ', ' + (DATENAME(dw, hdate) + ', ' + 
       DATENAME(mm, hdate) + ' '  + 
       DATENAME(dd, hdate))
        FROM @results
        WHERE id1 = 3
        FOR XML PATH('')
        ), 1, 2, '')
    ) AS h_date, 'Giving Day' AS h_name, 3 as id1) q
order by id1

【讨论】：

【解决方案3】：

这也有效：

declare @results table (hdate date, name varchar(100), id1 int)

insert into @results select cast('10-01-2015' as date), 'val1 1', 1
insert into @results select cast('10-02-2015' as date), 'val2 2', 2

insert into @results select cast('10-03-2015' as date), 'thanks 1', 3
insert into @results select cast('10-04-2015' as date), 'thanks 2', 3

select * FROM ( SELECT TOP 100 PERCENT (DATENAME(dw, hdate) + ', ' + 
        DATENAME(mm, hdate) + ' '  + 
      DATENAME(dd, hdate)) AS h_date, name AS h_name from @results where id1 in (1,2) 
ORDER BY id1)A
UNION 
select * FROM ( SELECT TOP 100 PERCENT (STUFF((
        SELECT ', ' + (DATENAME(dw, hdate) + ', ' + 
       DATENAME(mm, hdate) + ' '  + 
       DATENAME(dd, hdate))
        FROM @results
        WHERE id1 = 3
        FOR XML PATH('')
        ), 1, 2, '')
    ) AS h_date, 'Giving Day' AS h_name
    ) AS B

【讨论】：