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