Sql 如何使用case语句将多个值放入一列中？

我正在尝试将此表中的数据添加到现有查询：

我想创建一个名为“Assertions”的列，只想在值为“Y”的列名中输入。例如，对于Control_ID 13009（第一行），新的断言列将显示：

Control_ID    Assertions
13009        'Rights_Obligation, Valuation_Allocation, Existence_Occurence'

我尝试使用一个case-when语句，如下所示：

case when ca.PRESENTATION_DISCLOSURE = 'Y' then 'Presentation_Disclosure'
when ca.RIGHTS_OBLIGATION = 'Y' then 'Rights_Obligation'
when ca.VALUATION_ALLOCATION = 'Y' then 'Valuation_Allocation'
when ca.COMPLETENESS = 'Y' then 'Completeness'
when ca.EXISTENCE_OCCURRENCE = 'Y' then 'Existence_Occurence'
end as Assertions

---

此查询不起作用，因为它只是将第一个带有“Y”值的断言放入列中。如何修改查询，使其包含值为“Y”的所有断言？

您可以使用

CONCAT

，如下所示：

TRIM( ',' FROM 
    CONCAT(CASE when ca.PRESENTATION_DISCLOSURE = 'Y' then 'Presentation_Disclosure' END,
           CASE when ca.RIGHTS_OBLIGATION = 'Y' then ',Rights_Obligation' END,
           CASE when ca.VALUATION_ALLOCATION = 'Y' then ',Valuation_Allocation' END,
           CASE when ca.COMPLETENESS = 'Y' then ',Completeness' END,
           CASE when ca.EXISTENCE_OCCURRENCE = 'Y' then ',Existence_Occurence' END
          )
     ) as Assertions

在2014年，您可以使用以下查询，因为TRIM在2014年不可用

Stuff( 
    CONCAT(CASE when ca.PRESENTATION_DISCLOSURE = 'Y' then 'Presentation_Disclosure' END,
           CASE when ca.RIGHTS_OBLIGATION = 'Y' then ',Rights_Obligation' END,
           CASE when ca.VALUATION_ALLOCATION = 'Y' then ',Valuation_Allocation' END,
           CASE when ca.COMPLETENESS = 'Y' then ',Completeness' END,
           CASE when ca.EXISTENCE_OCCURRENCE = 'Y' then ',Existence_Occurence' END
          )
     1, 1, '') as Assertions

---

从SQL Server 2017开始，您可以使用

CONCAT\u WS（）

：

对于早期版本，

CONCAT（）

是一个选项：

STUFF(
   CONCAT (
      CASE when ca.PRESENTATION_DISCLOSURE = 'Y' then ', Presentation_Disclosure' END,
      CASE when ca.RIGHTS_OBLIGATION = 'Y' then ', Rights_Obligation' END,
      CASE when ca.VALUATION_ALLOCATION = 'Y' then ', Valuation_Allocation' END,
      CASE when ca.COMPLETENESS = 'Y' then ', Completeness' END,
      CASE when ca.EXISTENCE_OCCURRENCE = 'Y' then ', Existence_Occurence' END
   ), 1, 2, ''
) AS Assertions

---

什么是SQL Server版本？我使用的是SQL Server management studio 2014您也使用Oracle吗？如果没有，请删除该标记。

TRIM（）

可从SQL Server 2017获得。OP使用SQL Server Management Studio 2014，虽然它是一个cleint工具，但我猜SQL Server版本也是2014。修剪（“，”做什么？它删除尾随或前导的

，

STUFF(
   CONCAT (
      CASE when ca.PRESENTATION_DISCLOSURE = 'Y' then ', Presentation_Disclosure' END,
      CASE when ca.RIGHTS_OBLIGATION = 'Y' then ', Rights_Obligation' END,
      CASE when ca.VALUATION_ALLOCATION = 'Y' then ', Valuation_Allocation' END,
      CASE when ca.COMPLETENESS = 'Y' then ', Completeness' END,
      CASE when ca.EXISTENCE_OCCURRENCE = 'Y' then ', Existence_Occurence' END
   ), 1, 2, ''
) AS Assertions