SQL if / case语句-从数据库返回值

Question

I have trouble with sql command in MS Sql server ..... I would like to check names in table. in Column are eg Carl, Loius, Manfred, Jenny .... Is there any way, to create case or if statement :

Case  when name = 'Carl' then 'Man'
else Return original value(name) from table?

(Louis, Manfred, Jenny) ?

If yes, how can i achieve that ? Case statement? If statement? Thanks in advance

Answer 1

你可以做：

 select (Case when name = 'Carl' then 'Man' else name end)

Answer 2

you mean something like this ?

select name,
       case when name = 'Carl' then 'Man' 
            when name = 'Jenny' then 'women'
       else name end
from   yourtable

Answer 3

  Select case when name in ('Carl','Manfred',....) 
   Then 'Man' else 'Women' end as gender 
    from your_table

Answer 4

Another (shorter to write) option is to use nullif and isnull:

SELECT ISNULL(NULLIF(name, 'Carl'), name)) as name
FROM yourTable.

The NULLIF function will return null if both arguments are equale, and the ISNULL will return the first argument unless it's null - in that case it will return the second argument.