SQL基本操作——declare if lese while

declare

--第一种
declare @i int
set @i= (select COUNT(*) from t8)
select @i
--第二种
declare @i int
select @i= COUNT(*) from t8
print @i

if else

declare @num int
select @num=COUNT(*) from t8
if(@num>2)
    begin
        print '大于2'
    end
else
    begin
        print '小于2'
    end

while

--输出0-100
declare @i int
set @i=0
while(@i<=100)
begin
    print @i
    set @i=@i+ 1
end