同一字段根据不同条件更新的sql语句的写法

update test 
set 字段1=case when 条件1 then 值1 
              when 条件2 then 值2 
          end

示例：

update PMS_ProjectInfo set ProProgress=case when ProProgress+@ProProgress >=1 then 1 else ProProgress+@ProProgress end where ProjectID=@ProjectID

SQL条件判断语句

引用

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



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