sql - 替换列值

Question

我有这张 table ，

Name       Rating
A            2
B            1 
C            5
D            3
E            1
F            4

我有一个评级系统

1-Excellent, 2-Very Good, 3-Good, 4-OK, 5-Poor

我想知道是否可以替换表中的数值以获得以下结果表。

Name       Rating
A         Very Good
B         Excellent
C           Poor
D           Good
E         Excellent
F            OK

谢谢

Answer 1

我认为就地更新数据不是个好主意，最好存储评级的 ID，而不是数据的文本表示形式。但您可以查询表并将 int 替换为文本:

select
    Name,
    case Rating
        when 1 then 'Excellent'
        when 2 then 'Very Good,'
        when 3 then 'Good'
        when 4 then 'OK'
        when 5 then 'Poor'
    end as Rating
from <your table>

或者您可以创建一个查找表并与其连接

create table Rating (id int, desc nvarchar(128))

insert into Rating (id, desc)
select 1, 'Excellent' union all
select 2, 'Very good' union all
select 3, 'Good' union all
select 4, 'OK' union all
select 5, 'Poor'

select
    t.Name,
    R.desc as Rating
from <your table> as t
    left outer join Rating as R on R.id = t.Rating