sql简单语法

1、insert

insert into tb_shop (shop_id,shop_name,shop_num,shop_create_time) values(default,'奉先茶馆',32,'2019-07-25 19:30:23')

2、delete

delete from tb_shop

3、update

update tb_shop set shop_name='子龙面馆',shop_num=76

4、select

select * from tb_shop 
select shop_id,shop_name from tb_shop

5、count

汇总行数,即数据条数

select count(*) from tb_shop

6、sum

汇总字段的值

select sum(shop_num) from tb_shop

sum( if(xxx ) )

select sum(if(a>60), 1,0) AS aaa from tb_A

如果a>60，则将1累加到aaa，否在将0累加到aaa；1，0可以用某个字段代替，表示某个字段的值。