sql server中类似oracle中decode功能的函数

sqlserver 2008 写法

select t.PROJECTNAME,

    t.BUILDCONTENTSCALE,

    CASE t.PROJECTLEVEL

      WHEN '' THEN '国家重点'

      WHEN '' THEN '省重点'

      WHEN '' THEN '市重点'

      WHEN '' THEN '区/县重点'

      END AS PROJECTLEVEL,

    t.TOTALINVESTMENT,

    t.PROGRESSCONTENT,

    t.BUILDCOMPANY,

    t.CONTACTWAY,

    t.DUTYDEPT,

    t.REMARK

from t_iipms_applayprojects t

    where t.projecttype = ''

    and t.isvoided = '';

oracle中的写法

select t.PROJECTNAME,

       t.BUILDCONTENTSCALE,

       decode(t.PROJECTLEVEL,

              '',

              '国家重点',

              '',

              '省重点',

              '',

              '市重点',

              '',

              '区/县重点') as PROJECTLEVEL,

       t.TOTALINVESTMENT,

       t.PROGRESSCONTENT,

       t.BUILDCOMPANY,

       t.CONTACTWAY,

       t.DUTYDEPT,

       t.REMARK

  from t_iipms_applayprojects t

 where t.projecttype = ''

   and t.isvoided = '';

细节对比看效果很明显：SQL Server 2008中

CASE t.PROJECTLEVEL

      WHEN '' THEN '国家重点'

      WHEN '' THEN '省重点'

      WHEN '' THEN '市重点'

      WHEN '' THEN '区/县重点'

      END AS PROJECTLEVEL

Oracle 10g中

decode(t.PROJECTLEVEL,

              '',

              '国家重点',

              '',

              '省重点',

              '',

              '市重点',

              '',

              '区/县重点') as PROJECTLEVEL

原文地址：

https://blog.csdn.net/hu_shengyang/article/details/10533865