Question

我要做的是对同一列使用多个CASE WHEN条件。

以下是我的查询代码：

   SELECT   Url='',
            p.ArtNo,
            p.[Description],
            p.Specification,
            CASE 
            WHEN 1 = 1 or 1 = 1 
               THEN 1 
               ELSE 0 
            END as Qty,
            p.NetPrice,
            [Status] = 0
      FROM  Product p (NOLOCK)

但是，我想要做的是对同一列“qty”使用多个WHEN。

如以下代码所示：

IF
// CODE
ELSE IF
// CODE
ELSE IF
// CODE
ELSE
// CODE

Answer 1

有two formats of case expression。您可以使用CASE作为多个WHEN进行CASE WHEN Col1 = 1 OR Col3 = 1 THEN 1 WHEN Col1 = 2 THEN 2 ... ELSE 0 END as Qty

CASE

或一个简单的CASE Col1 WHEN 1 THEN 11 WHEN 2 THEN 21 ELSE 13 END表达式

CASE

在 CASE中

或 CASE WHEN Col1 < 2 THEN CASE Col2 WHEN 'X' THEN 10 ELSE 11 END WHEN Col1 = 2 THEN 2 ... ELSE 0 END as Qty ;

{{1}}

Answer 2

只要使用这个，你必须在课时使用更多。

SELECT   Url='',
         p.ArtNo,
         p.[Description],
         p.Specification,
         CASE 
         WHEN 1 = 1 or 1 = 1 
            THEN 1 
         WHEN 2 = 2
             THEN 2
         WHEN 3 = 3
              THEN 3
          ELSE 0 
        END as Qty,
        p.NetPrice,
        [Status] = 0
  FROM  Product p (NOLOCK)

Answer 3

当有多个条件时，您可以使用下面的案例示例。

SELECT
  id,stud_name,
  CASE
    WHEN marks <= 40 THEN 'Bad'
    WHEN (marks >= 40 AND
      marks <= 100) THEN 'good'
    ELSE 'best'
  END AS Grade
FROM Result

Answer 4

这可以是在单个语句上执行不同测试的有效方法

select
case colour_txt 
  when 'red' then 5 
  when 'green' then 4 
  when 'orange' then 3
else 0 
end as Pass_Flag

这只适用于平等比较！

Answer 5

    case when first_condition
      then first_condition_result_true
    else
      case when second_condition 
        then second_condition_result_true
      else
          second_condition_result_false                              
      end
    end
  end as qty

Answer 6

case 
    when a.REASONID in ('02','03','04','05','06') then
        case b.CALSOC 
            when '1' then 'yes' 
            when '2' then 'no' 
            else 'no' 
        end
    else 'no' 
end

Answer 7

我有一个类似但是处理日期。查询显示上个月的所有项目，无条件下工作到1月。为了使其正常工作，需要添加年份和月份变量

declare @yr int
declare @mth int

set @yr=(select case when month(getdate())=1 then YEAR(getdate())-1 else YEAR(getdate())end)
set @mth=(select case when month(getdate())=1 then month(getdate())+11 else month(getdate())end)

现在我只需将变量添加到条件中： ...

(year(CreationTime)=@yr and MONTH(creationtime)=@mth)

Answer 8

结合所有条件

select  a.* from tbl_Company a

where  a.Company_ID NOT IN (1,2)  

AND (   
        (0 = 
            CASE WHEN (@Fromdate = '' or @Todate='')
                THEN 0 
                ELSE 1  
            END
        )      -- if 0=0 true , if 0=1 fails (filter only when the fromdate and todate is present)
                OR
        (a.Created_Date between @Fromdate and @Todate )                 
    )

Answer 9

类似这样的情况，两个条件两列

SELECT ITEMSREQ.ITEM AS ITEM,
       ITEMSREQ.CANTIDAD AS CANTIDAD,
       (CASE  WHEN ITEMSREQ.ITEMAPROBADO=1 THEN 'APROBADO'
              WHEN ITEMSREQ.ITEMAPROBADO=0 THEN 'NO APROBADO'
        END) AS ITEMS,
        (CASE 
              WHEN ITEMSREQ.ITEMAPROBADO = 0 
              THEN CASE WHEN REQUISICIONES.RECIBIDA IS NULL  THEN 'ITEM NO APROBADO PARA ENTREGA' END
              WHEN ITEMSREQ.ITEMAPROBADO = 1 
              THEN CASE WHEN REQUISICIONES.RECIBIDA IS NULL THEN 'ITEM AUN NO RECIBIDO' 
                        WHEN REQUISICIONES.RECIBIDA=1 THEN 'RECIBIDO' 
                        WHEN REQUISICIONES.RECIBIDA=0 THEN 'NO RECIBIDO' 
                       END
              END)
              AS RECIBIDA
 FROM ITEMSREQ
      INNER JOIN REQUISICIONES ON
      ITEMSREQ.CNSREQ = REQUISICIONES.CNSREQ

Answer 10

一个案例只需要多个When才能表现得像if.. Elseif else..

   Case when 1=1       //if
   Then
    When 1=1              //else if
     Then.... 
    When .....              //else if
    Then 
    Else                      //else
   ....... 
     End

如何使用SQL Server 2008执行多个CASE WHEN条件？

10 个答案: