1：update 時(shí)做檢查使用
        

        update
      
       mw_contract 
      
        set
      
       payTimes
      
        =
      
      
        (


      
      
        case
      
      
        when
      
       payTimes
      
        >
      
      
        0
      
      
        then
      
       payTimes
      
        -
      
      
        1
      
      
        else
      
       payTimes 
      
        end
      
      
        

)
      
      
        where
      
       contractNo
      
        =
      
      
        '
      
      
        2015001
      
      
        '
      
      
        ;



2：select時(shí)使用


      
      
        select
      
      
        case
      
      
        when
      
       payTimes
      
        >
      
      
        0
      
      
        then
      
       payTimes
      
        -
      
      
        1
      
      
        else
      
       payTimes 
      
        end
      
      
         payTimes


      
      
        from
      
       mw_contract;