Sql server 2008 用于CASE语句的sql别名列名

我有一个sql查询，如下所示

select Site,DataSource,
(SELECT CASE 
   WHEN DataSource = 'RFQ' THEN 'ChangeOperator' 
   ELSE 'SameOperator' 
  END) AS OperatorScenario,

  (SELECT CASE 
   WHEN OperatorScenario = 'ChangeOperator' THEN '1' 
   ELSE '022' 
  END) AS OperatorScenario2
from tablename

(SELECT CASE 
   WHEN 'OperatorScenario' = 'ChangeOperator' THEN '1' 
   ELSE '022' 
  END) AS OperatorScenario2

当我执行此查询时，得到的异常为无效列名运算符Scenario。所以我在第二次查询中尝试在别名中使用单个代码，如下所示

select Site,DataSource,
(SELECT CASE 
   WHEN DataSource = 'RFQ' THEN 'ChangeOperator' 
   ELSE 'SameOperator' 
  END) AS OperatorScenario,

  (SELECT CASE 
   WHEN OperatorScenario = 'ChangeOperator' THEN '1' 
   ELSE '022' 
  END) AS OperatorScenario2
from tablename

(SELECT CASE 
   WHEN 'OperatorScenario' = 'ChangeOperator' THEN '1' 
   ELSE '022' 
  END) AS OperatorScenario2

所以它总是执行其他部分。请给我一些建议。 当做

---

sangeetha

主要问题是不能在同一查询中引用别名。此外，还有括号和一个额外的

SELECT

关键字，使它看起来像是一个子查询，而我认为您并不打算这样做（您没有

FROM

子句）

您可以再次复制整个内容（在此过程中修复查询）：

或者，简化：

SELECT Site, DataSource,
    CASE 
       WHEN DataSource = 'RFQ' THEN 'ChangeOperator' 
       ELSE 'SameOperator' 
    END AS OperatorScenario,

   CASE 
       WHEN DataSource = 'RFQ' THEN '1' 
       ELSE '022' 
   END AS OperatorScenario2
from tablename

---

或者使用CTE（再次修复您的查询）：

---

您无法在此查询中访问同一级别的别名，请使用子查询或cte：

WITH cte 
     AS (SELECT site, 
                datasource, 
                CASE 
                  WHEN datasource = 'RFQ' THEN 'ChangeOperator' 
                  ELSE 'SameOperator' 
                END AS OperatorScenario 
         FROM   dbo.tablename) 
SELECT site, 
       datasource, 
       operatorscenario, 
       CASE 
         WHEN operatorscenario = 'ChangeOperator' THEN '1' 
         ELSE '022' 
       END AS OperatorScenario2 
FROM   cte 

---

请注意，我还删除了额外的Paranthese，并在

案例中选择了
我在开始时设置了别名，如下所示：

SELECT [ALIAS] = CASE....

你的建议是：

SELECT Site, DataSource,   
   [OperatorScenario] = CASE 
       WHEN DataSource = 'RFQ' THEN 'ChangeOperator' ELSE 'SameOperator' 
   END,

   [OperatorScenario2] = CASE 
       WHEN DataSource = 'RFQ' THEN '1' ELSE '022' 
   END
from tablename