如何在SQL查询中包含Case语句

我想在我的sql查询中合并这个Case语句，但我收到了以下错误：无效的列名：MsgID。是否有人对代码如何无错误运行有任何建议？请注意，我使用的是SQLServerManagementStudio 2008

个案陈述： 原始查询： 提供错误信息的查询：

---

导致问题的不是case语句，而是CTE声明-内部的

SELECT

语句中没有

MsgId

列，因此不能将其包含在外部的列列表中。

您没有将

MsgId

从（大概）

jnlist

暴露为

A

，这里：

FROM (  SELECT  ItemId,
            CONVERT(VARCHAR(18),[Date]) [Date],
            Parms,
            [OBJECT]
    FROM JnlList
    WHERE UserCode = 'Automation') A

因此，您可能只需要将

MsgId

添加到

SELECT

子句中。如果不是那张桌子上的，告诉我们它是从哪里来的

    ;WITH CTE AS
    (
    SELECT  CONVERT(DATETIME,LEFT([Date],8)+' '+
                         SUBSTRING([Date],10,2)+':'+
                         SUBSTRING([Date],12,2)+':'+
                         SUBSTRING([Date],14,2)+'.'+
                         RIGHT([Date],3)) [Date],
        ItemId,
        Parms,
        [OBJECT]
   FROM (  SELECT  ItemId,
                CONVERT(VARCHAR(18),[Date]) [Date],
                Parms,
                [OBJECT]
        FROM JnlList
        WHERE UserCode = 'Automation') A
   )
   SELECT  ItemId,
    CONVERT(DATE,[Date]) [Date],
    CONVERT(VARCHAR(10),[Date],108) AS [Time],
    SUBSTRING(Parms,1,6) +' Was removed from:' RemovalPath,
    [OBJECT] [Move List:]
   FROM CTE
   WHERE [Date] >= CONVERT(DATE,DATEADD(DAY,-4,GETDATE()))

  WITH CTE AS
  (
  SELECT  CONVERT(DATETIME,LEFT([Date],8)+' '+
                         SUBSTRING([Date],10,2)+':'+
                         SUBSTRING([Date],12,2)+':'+
                         SUBSTRING([Date],14,2)+'.'+
                         RIGHT([Date],3)) [Date],
        ItemId,
        MsgID,
        Parms,
        [OBJECT]
 FROM (  SELECT  ItemId,
                CONVERT(VARCHAR(18),[Date]) [Date],
                Parms,
                [OBJECT]
        FROM JnlList
        WHERE UserCode = 'Automation') A
 )
 SELECT  ItemId, MsgID,
    CONVERT(DATE,[Date]) [Date],
    CONVERT(VARCHAR(10),[Date],108) AS [Time],
    CASE WHEN MsgID = '1' THEN SUBSTRING(Parms,1,6) +' Was removed from:'
    WHEN MsgID = '2' THEN 'This Move List has been cleared of all its media'
    ELSE '' -- Optional Else
    END AS [RemovalPath],
    [OBJECT] [Move List:]
 FROM CTE
 WHERE [Date] >= CONVERT(DATE,DATEADD(DAY,-4,GETDATE()))

FROM (  SELECT  ItemId,
            CONVERT(VARCHAR(18),[Date]) [Date],
            Parms,
            [OBJECT]
    FROM JnlList
    WHERE UserCode = 'Automation') A