35

如果我通过，在 MySQL 查询中：

  case guides.Gud_Publish_Date 
     when null then "Unscheduled" 
     else "Forth Coming Titles" 
  end

那么它正在考虑一切都是空的，即使 Gud_Publish_Date 也有价值。完整的 SQL 语句是

SELECT guides.Gud_Id
    , guides.Gud_Image
    , guides.Gud_SubEditor
    , guides.Gud_Reprint_Status
    , guides.Gud_Publish_Date
    , guides.Gud_Img_Chk
    , guides.Gud_Published
    , guides.Gud_View
    , (
        CASE guides.Gud_Publish_Date
            WHEN NULL
                THEN "Unscheduled"
            ELSE "Forth Coming Titles"
            END
        ) AS Schedules
FROM guides

有谁能够帮我？提前致谢

4

4 回答 4

73

尝试使用IF

SELECT guides.Gud_Id
    , guides.Gud_Image
    , guides.Gud_SubEditor
    , guides.Gud_Reprint_Status
    , guides.Gud_Publish_Date
    , guides.Gud_Img_Chk
    , guides.Gud_Published
    , guides.Gud_View
    , IF(guides.Gud_Publish_Date IS NULL,'Unscheduled','Forth Coming Titles') 
             AS Schedules
FROM guides

或者如果你真的想要CASE

SELECT guides.Gud_Id
    , guides.Gud_Image
    , guides.Gud_SubEditor
    , guides.Gud_Reprint_Status
    , guides.Gud_Publish_Date
    , guides.Gud_Img_Chk
    , guides.Gud_Published
    , guides.Gud_View
    , (
        CASE 
            WHEN guides.Gud_Publish_Date IS NULL
            THEN 'Unscheduled'
            ELSE 'Forth Coming Titles'
        END
      ) AS Schedules
FROM guides
于 2012-11-12T07:08:53.277 回答
14

我发现了这个 - 几个月前的帖子。使用COALESCERajan 预期的选项，您可以这样做，

SELECT guides.Gud_Id
    , guides.Gud_Image
    , guides.Gud_SubEditor
    , guides.Gud_Reprint_Status
    , guides.Gud_Publish_Date
    , guides.Gud_Img_Chk
    , guides.Gud_Published
    , guides.Gud_View
    , CASE COALESCE(guides.Gud_Publish_Date, 0)
          WHEN 0 THEN 'Unscheduled'
                 ELSE 'Forth Coming Titles'
          END  AS Schedules
FROM guides

上面的代码假设guides.Gud_Publish_Date不能取值 0，我可以这样做，因为它是一个日期。如果不是这种情况，您可以将 0 更改为另一个无法采用的值；也许你最喜欢3.1415的 float like 或 null identifier 'null'。

于 2015-01-08T17:05:23.167 回答
5 
SELECT guides.Gud_Id
    , guides.Gud_Image
    , guides.Gud_SubEditor
    , guides.Gud_Reprint_Status
    , guides.Gud_Publish_Date
    , guides.Gud_Img_Chk
    , guides.Gud_Published
    , guides.Gud_View
    , (
        CASE WHEN guides.Gud_Publish_Date IS NULL
            THEN "Unscheduled"
            ELSE "Forth Coming Titles"
            END
        ) AS Schedules
FROM guides
于 2012-11-12T07:10:26.663 回答
-2

尝试这个

SELECT guides.Gud_Id
    , guides.Gud_Image
    , guides.Gud_SubEditor
    , guides.Gud_Reprint_Status
    , guides.Gud_Publish_Date
    , guides.Gud_Img_Chk
    , guides.Gud_Published
    , guides.Gud_View
    , coalesce((
        CASE guides.Gud_Publish_Date
            WHEN NULL
                THEN 'Unscheduled'
            ELSE 'Forth Coming Titles'
            END
        ), 'Unscheduled') AS Schedules
FROM guides
于 2014-02-12T04:36:14.767 回答