mysql order by

标签：mysql

order by

排序：在结果集出来之后才有意义 必须在where ,group by ，having 之后

desc（降序）/asc(升序)

用字段排序  

用shop_price 降序排列

select goods_name,cat_id,shop_price from goods where cat_id=4 order by shop_price desc;

多个排序选择，先根据cat_id,然后shop_price

select cat_id,shop_price,goods_name from goods order by cat_id ,shop_price;

limit限制 limit [pos, 可选偏移量] 数量 

升序排列 取出前十名

select goods_id,goods_name from goods where cat_id=3 order by shop_price asc limit 10;

价格最高的前五名

mysql> select goods_name ,shop_price from goods order by shop_price desc limit 0,5;

等同

mysql> select goods_name ,shop_price from goods order by shop_price desc limit 5;

+----------------+------------+

| goods_name     | shop_price |

+----------------+------------+

| 多普达Touch HD      |    5999.00 | 

| 诺基亚N96           |    3700.00 | 

| 诺基亚N85           |    3010.00 | 

| testPhone      |    3000.00 | 

| 夏新T5             |    2878.00 | 

+----------------+------------+

价格最高的 从第三名开始的三名（或者说是第三名到第五名）

mysql> select goods_name ,shop_price from goods order by shop_price desc limit 2,3;

+------------+------------+

| goods_name | shop_price |

+------------+------------+

| 诺基亚N85       |    3010.00 | 

| testPhone  |    3000.00 | 

| 夏新T5         |    2878.00 | 

+------------+------------+

取出价格最高的商品

mysql> select goods_name ,shop_price from goods order by shop_price desc limit 1;

+----------------+------------+

| goods_name     | shop_price |

+----------------+------------+

| 多普达Touch HD      |    5999.00 | 

+----------------+------------+

技巧 ：[判断where] [分组group_by] [过滤having] [排序order by] [筛选limit]

取出每个类型中 最新的产品

select cat_id, goods_id ,goods_name from(

(select cat_id,goods_id ,goods_name from goods order by cat_id desc,goods_id desc ) as tmp

)group by cat_id order by cat_id desc;

select cat_id,goods_id ,goods_name from goods where goods_id in (

select max(goods_id) from goods group by cat_id 

) order by cat_id desc;

查询出来的结果可以是

单列单行 可以用=   再次过滤

单列多行 可以用in  再次过滤

多列多行 可以用from 再次过滤

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mysql order by

标签：mysql

原文地址：http://codeyi.blog.51cto.com/11082384/1732465