Question

我有以下查询，用于返回逗号分隔的结果。

SELECT STUFF
(
    (
        SELECT ',' + em.EMAIL 
        FROM(
            SELECT  DISTINCT USR.EMAIL AS EMAIL
          FROM PRNCPLS A, PRNCPLS B, USER_INFO USR,
          RELATIONSHIPS C
          WHERE A.ID = C.PARENTID 
          AND B.ID = C.CHILDID
          AND A.TYPE = 'USER' and B.TYPE = 'ROLE'
          AND A.ID = USR.ID
          and B.NAME = 'Approver'
          AND USR.EMAIL IS NOT NULL) em
        ORDER BY em.EMAIL FOR XML PATH('')
    ),
     1, 1, ''
) AS Output

我需要以某种方式更新此查询，使得SQL语句的第一行（而不是输出）始终像这样

SELECT EMAIL FROM

这是必需的，因为出于某种原因，我使用的工具期望第一行中有FROM，而SELECT子句中只有一个元素。我的查询实际上只返回一个元素，所以我希望以某种方式更新它。

预期输出-abcd @ gmail.com，1234 @ yahoo.com，xyz @ gmail.com

任何帮助将不胜感激。

Answer 1

您尝试过

SELECT 'SELECT EMAIL FROM ' + STUFF
(
    (
        SELECT ',' + em.EMAIL 
        FROM(
            SELECT  DISTINCT USR.EMAIL AS EMAIL
          FROM PRNCPLS A, PRNCPLS B, USER_INFO USR,
          RELATIONSHIPS C
          WHERE A.ID = C.PARENTID 
          AND B.ID = C.CHILDID
          AND A.TYPE = 'USER' and B.TYPE = 'ROLE'
          AND A.ID = USR.ID
          and B.NAME = 'Approver'
          AND USR.EMAIL IS NOT NULL) em
        ORDER BY em.EMAIL FOR XML PATH('')
    ),
     1, 1, ''
) AS Output;

还是还有关于数据格式的更多信息？

Answer 2

您是否尝试过

SELECT 'SELECT EMAIL FROM '
UNION
... Your existing query

Answer 3

SELECT EMAIL FROM (

SELECT STUFF
(
    (
        SELECT ',' + em.EMAIL 
        FROM(
            SELECT  DISTINCT USR.EMAIL AS EMAIL
          FROM PRNCPLS A, PRNCPLS B, USER_INFO USR,
          RELATIONSHIPS C
          WHERE A.ID = C.PARENTID 
          AND B.ID = C.CHILDID
          AND A.TYPE = 'USER' and B.TYPE = 'ROLE'
          AND A.ID = USR.ID
          and B.NAME = 'Approver'
          AND USR.EMAIL IS NOT NULL) em
        ORDER BY em.EMAIL FOR XML PATH('')
    ),
     1, 1, '') AS EMAIL
) AS Output

当心“ EMAIL ...”：

“选择电子邮件...”
“ ... 1,1，''）电子邮件...”。

Answer 4

您可以像这样包装几乎所有SELECT：

SELECT t.SomeColumn FROM
(
     place your existing SELECT here
) t;

这不适用于CTE查询，但是CTE本身可以转移到子查询中。

提示：如果可能，请尽量避免使用老式的联接。 Sami在评论中提供了一个很好的链接...

在一个元素中返回SQL Server中逗号分隔的值

4 个答案: