mysql 查

select count(*) from table_name;

select * from goods where shop_price >= 100 and shop_price <= 500;
select * from goods where shop_price between 100 and 500;

select * from goods where shop_price <=100 and shop_price >= 500;
select * from goods where shop_price not between 100 and 500;

select * from goods where cat_id!=3 and cat_id!=11;
select * from goods where cat_id not in(3,11);

select goods_id,(market_price-shop_price) as chajia ,goods_name from goods ;

select goods_id,(market_price-shop_price) as chajia ,goods_name from goods where (market_price - shop_price) > 200;

select goods_id,(market_price-shop_price) as chajia ,goods_name from goods where chajia > 200;(错误的)

select goods_id,(market_price-shop_price) as chajia ,goods_name from goods having chajia>200;

update mian set num = floor(num/10)*10 where num between 20 and 39;

select goods_id ,goods_name,substring(goods_name,4) from goods where goods_name like '诺基亚%';

select goods_id ,goods_name,concat('htc',substring(goods_name,4)) from goods where goods_name like '诺基亚%';

update goods 
set goods_name = concat('htc',substring(goods_name,4))
where goods_name like '诺基亚%' and cat_id=4;