SQL 条件语句

第一种：
SELECT
CASE

     WHEN
price IS NULL THEN
'Not yet priced'
     WHEN
price < 10 THEN
'Very Reasonable Title'
     WHEN
price >= 10 AND
price < 20 THEN
'Coffee Table Title'
     ELSE
'Expensive book!'
     END
AS
"Price Category",
     CONVERT(varchar(20), title) AS "Shortened Title"
from
pubs.dbo.titles
ORDER BY
price
 第二种：
SELECT au_fname, au_lname,
   CASE state
      WHEN 'CA' THEN 'California'
      WHEN 'KS' THEN 'Kansas'
      WHEN 'TN' THEN 'Tennessee'
      WHEN 'OR' THEN 'Oregon'
      WHEN 'MI' THEN 'Michigan'
      WHEN 'IN' THEN 'Indiana'
      WHEN 'MD' THEN 'Maryland'
      WHEN 'UT' THEN 'Utah'
      END AS StateName
from pubs.dbo.authors
ORDER BY au_lname
本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/hbzhangjian/archive/2006/07/31/1003684.aspx
SELECT top 2 id, uid,cn,
   CASE len(cn)
      WHEN 3 THEN 'California'
      WHEN 2 THEN 'Kansas'     
      END AS StateName
from conf_users