如何在 sql 的 case 语句中执行计算并将其显示为带有其他值的注释？

Question

table给定叫LEAVE LEAVE 有 2 列 Leavetype，类型为 varchar 类型，allocated_days 为 number 类型。

离开：

休假类型allocated_days 生病 5 婚姻 10 事故 20 产妇 90

公司更新了它的政策，现在变化是

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leavetype             allocated_days
     sick                   add  5 days
     marriage               add  5 days
     accident               substract 5 days
     maternity              multiply with 2

在 sql 案例的帮助下产生这个输出

离开：

leavetype             allocated_days    revised policy
     sick                   5              10
     marriage               10             15
     accident               20             15
     maternity              90             180

我试过的代码是：

select leavetype,allocated_days
 case 
    when leavetype='sick' then  (allocated_days+5)
    when leavetype='marriage' then (allocated_days+5)
    when leavetype='accident' then (allocated_days-5)
    when leavetype='maternity' then (allocatef_days*2)
 else allocated_days
end "revised policy" from leave;

错误说：

from keyword not properly placed

我是一个学习有志者，我找不到任何相关资源可以参考和学习，请帮助

Answer 1

缺少逗号，但您也可以稍微简化您的查询：

select leavetype,allocated_days,
 case 
    when leavetype in ('sick','marriage') then (allocated_days+5)    
    when leavetype='accident' then (allocated_days-5)
    when leavetype='maternity' then (allocated_days*2)
 else allocated_days
end "revised policy" from leave;