select 语句

1.into 插入语句

创建一个新表，并包含原表的两列数据

if OBJECT_ID('tb_jishu') is not null
   drop table tb_jishu

select 国家,产品 into tb_jishu from jishu

select * from tb_jishu

2.[ ],[^]通配符，betweeen

select * from table where age like '2[2-4]'--22，23，24岁

select * from table where age between 22 and 24

select * from table where age like '2[^2-4]'--不在22，23，24

select * from table where age not between 22 and 24

3.any,some,all

>all,大于最大值，>any/>some,大于最小值

4.top

select top 3 * from jishu--返回表的前3行

5.union 合并表查询

6.根据不同条件更新同一字段

update testdate
set num1=
(case 
when name=1 then  10
when name=2 then  20
when name=3 then  30
END)

where 0=0

update testdate set num2 = 
(case 
when name like '%jing%' then 
(case 
when name like '%xia%' then 40
when name not like '%xia%' then 30
 end) 
when name not like '%jing%' then 20
end)