Sql语句：IF ELSE CASE WHEN WHILE CONTINUE BREAK

--声明两个变量，使用select关键字给变量赋值，值来源自数据表

declare @Name nvarchar(50)
declare @email nvarchar(50)

select @Name = (select clientid from client where clientid = '1'),@email = (select email　from client where clientid = '1')

print @Name
print @email

--查询出Users表中username列包含"["的记录，使用2种方法

select * from Users	where username like '%\[%' escape '\'

select * from Users where username like '%[[]%'


--使用IF Else 判断两个数的大小

declare @i1 int
declare @i2 int

select @i1 = 100 ,@i2 = 20

if(@i1>@i2)
begin
print convert(varchar(50),@i1)+' 比'+convert(varchar(50),@i2)+' 大'
end 

else
begin
print convert(varchar(50),@i1)+' 比'+convert(varchar(50),@i2)+' 小'
end

--使用Case When 将Score表中的score_1字段转义输出为

select *,备注 = case 
when score_1<60 then '不及格'
when score_1>=60 and score_1<=80 then '良好'
when score_1>80 and score_1<=100 then '优秀'
else '异常(Error)'
end
from Score


--利用循环控制（While,Continue,Break）打印输出以下字符：

declare @num int

set @num = 0

while(@num<100)
begin 


set @num =@num + 1

if(@num=6 or @num = 7)
continue;

if(@num>9)
break;

print @num

end--声明两个变量，使用select关键字给变量赋值，值来源自数据表

declare @Nam