【数据库】同一字段根据不同条件更新的sql语句的写法

语法：

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

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