游标 cursor 使用方法

declare mc cursor for SELECT [id],[name] ,[age] FROM [tb]
DECLARE @id nvarchar(50)
DECLARE @name nvarchar(50)
DECLARE @age int
open mc
fetch next from mc INTO @id,@name,@age 
while @@fetch_status = 0
Begin
select @id,@name,@age
fetch next from mc INTO @id,@name,@age 

end
 
close mc
deallocate mc