**创建**
```
create procedure test1(in name int)
begin
declare username varchar(20);
case name
when 1 then
set username=1;
when 2 then
set username=2;
else
set username='未设置名称';
end case;
update a set name = username;
end
$$;
```
**查询操作使用case**
```
select (case sex when 1 then '男' else '女' end) as'性别' from a;
```
