A tricky SQL statement, ask prawn for help

txgy_hero

There are three fields a, b, and c in the table, where the value of field a is taken when c = 0, and the value of field b is taken when c = 1, how to write such a SQL statement? Thank you

prajna

select (case when c = 0 then a else b end) as val from table

3972500

create table tablename (
a char (10),
b char (10),
c int)

insert into tablename
select 'aa', 'bb', 0
union all
select 'cc', 'dd', 1

select tablename. *, value = case when c = 0 then a else b end from tablename

result:
a b c value
aa bb 0 aa
cc dd 1 dd