如果不指定排序 默认是按照id字段 从小到大排序的 升序
mysql> select * from employee;
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id |
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
| 1 | alex | male | 78 | 2015-03-02 | teacher | NULL | 1000000.31 | 401 | 1 |
| 2 | yuanhao | male | 73 | 2014-07-01 | teacher | NULL | 3500.00 | 401 | 1 |
| 3 | liwenzhou | male | 28 | 2012-11-01 | teacher | NULL | 2100.00 | 401 | 1 |
| 4 | jingliyang | female | 18 | 2011-02-11 | teacher | NULL | 9000.00 | 401 | 1 |
| 5 | jinxin | male | 18 | 1900-03-01 | teacher | NULL | 30000.00 | 401 | 1 |
| 6 | 成龙 | male | 48 | 2010-11-11 | teacher | NULL | 10000.00 | 401 | 1 |
| 7 | 歪歪 | female | 48 | 2015-03-11 | sale | NULL | 3000.13 | 402 | 2 |
| 8 | 丫丫 | female | 38 | 2010-11-01 | sale | NULL | 2000.35 | 402 | 2 |
| 9 | 丁丁 | female | 18 | 2011-03-12 | sale | NULL | 1000.37 | 402 | 2 |
| 10 | 星星 | female | 18 | 2016-05-13 | sale | NULL | 3000.29 | 402 | 2 |
| 11 | 格格 | female | 28 | 2017-01-27 | sale | NULL | 4000.33 | 402 | 2 |
| 12 | 张野 | male | 28 | 2016-03-11 | operation | NULL | 10000.13 | 403 | 3 |
| 13 | 程咬金 | male | 18 | 1997-03-12 | operation | NULL | 20000.00 | 403 | 3 |
| 14 | 程咬银 | female | 18 | 2013-03-11 | operation | NULL | 19000.00 | 403 | 3 |
| 15 | 程咬铜 | male | 18 | 2015-04-11 | operation | NULL | 18000.00 | 403 | 3 |
| 16 | 程咬铁 | female | 18 | 2014-05-12 | operation | NULL | 17000.00 | 403 | 3 |
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
16 rows in set (0.10 sec)
order by 不指定 asc 默认就是升序
需求 按照年龄从小到大 排序 升序
asc 是升序
mysql> select * from employee order by age asc;
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id |
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
| 16 | 程咬铁 | female | 18 | 2014-05-12 | operation | NULL | 17000.00 | 403 | 3 |
| 15 | 程咬铜 | male | 18 | 2015-04-11 | operation | NULL | 18000.00 | 403 | 3 |
| 14 | 程咬银 | female | 18 | 2013-03-11 | operation | NULL | 19000.00 | 403 | 3 |
| 13 | 程咬金 | male | 18 | 1997-03-12 | operation | NULL | 20000.00 | 403 | 3 |
| 10 | 星星 | female | 18 | 2016-05-13 | sale | NULL | 3000.29 | 402 | 2 |
| 9 | 丁丁 | female | 18 | 2011-03-12 | sale | NULL | 1000.37 | 402 | 2 |
| 5 | jinxin | male | 18 | 1900-03-01 | teacher | NULL | 30000.00 | 401 | 1 |
| 4 | jingliyang | female | 18 | 2011-02-11 | teacher | NULL | 9000.00 | 401 | 1 |
| 12 | 张野 | male | 28 | 2016-03-11 | operation | NULL | 10000.13 | 403 | 3 |
| 3 | liwenzhou | male | 28 | 2012-11-01 | teacher | NULL | 2100.00 | 401 | 1 |
| 11 | 格格 | female | 28 | 2017-01-27 | sale | NULL | 4000.33 | 402 | 2 |
| 8 | 丫丫 | female | 38 | 2010-11-01 | sale | NULL | 2000.35 | 402 | 2 |
| 7 | 歪歪 | female | 48 | 2015-03-11 | sale | NULL | 3000.13 | 402 | 2 |
| 6 | 成龙 | male | 48 | 2010-11-11 | teacher | NULL | 10000.00 | 401 | 1 |
| 2 | yuanhao | male | 73 | 2014-07-01 | teacher | NULL | 3500.00 | 401 | 1 |
| 1 | alex | male | 78 | 2015-03-02 | teacher | NULL | 1000000.31 | 401 | 1 |
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
16 rows in set (0.00 sec)
不加asc
mysql> select * from employee order by age ;
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id |
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
| 16 | 程咬铁 | female | 18 | 2014-05-12 | operation | NULL | 17000.00 | 403 | 3 |
| 15 | 程咬铜 | male | 18 | 2015-04-11 | operation | NULL | 18000.00 | 403 | 3 |
| 14 | 程咬银 | female | 18 | 2013-03-11 | operation | NULL | 19000.00 | 403 | 3 |
| 13 | 程咬金 | male | 18 | 1997-03-12 | operation | NULL | 20000.00 | 403 | 3 |
| 10 | 星星 | female | 18 | 2016-05-13 | sale | NULL | 3000.29 | 402 | 2 |
| 9 | 丁丁 | female | 18 | 2011-03-12 | sale | NULL | 1000.37 | 402 | 2 |
| 5 | jinxin | male | 18 | 1900-03-01 | teacher | NULL | 30000.00 | 401 | 1 |
| 4 | jingliyang | female | 18 | 2011-02-11 | teacher | NULL | 9000.00 | 401 | 1 |
| 12 | 张野 | male | 28 | 2016-03-11 | operation | NULL | 10000.13 | 403 | 3 |
| 3 | liwenzhou | male | 28 | 2012-11-01 | teacher | NULL | 2100.00 | 401 | 1 |
| 11 | 格格 | female | 28 | 2017-01-27 | sale | NULL | 4000.33 | 402 | 2 |
| 8 | 丫丫 | female | 38 | 2010-11-01 | sale | NULL | 2000.35 | 402 | 2 |
| 7 | 歪歪 | female | 48 | 2015-03-11 | sale | NULL | 3000.13 | 402 | 2 |
| 6 | 成龙 | male | 48 | 2010-11-11 | teacher | NULL | 10000.00 | 401 | 1 |
| 2 | yuanhao | male | 73 | 2014-07-01 | teacher | NULL | 3500.00 | 401 | 1 |
| 1 | alex | male | 78 | 2015-03-02 | teacher | NULL | 1000000.31 | 401 | 1 |
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
16 rows in set (0.00 sec)
降序 desc
mysql> select * from employee order by age desc;
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id |
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
| 1 | alex | male | 78 | 2015-03-02 | teacher | NULL | 1000000.31 | 401 | 1 |
| 2 | yuanhao | male | 73 | 2014-07-01 | teacher | NULL | 3500.00 | 401 | 1 |
| 7 | 歪歪 | female | 48 | 2015-03-11 | sale | NULL | 3000.13 | 402 | 2 |
| 6 | 成龙 | male | 48 | 2010-11-11 | teacher | NULL | 10000.00 | 401 | 1 |
| 8 | 丫丫 | female | 38 | 2010-11-01 | sale | NULL | 2000.35 | 402 | 2 |
| 3 | liwenzhou | male | 28 | 2012-11-01 | teacher | NULL | 2100.00 | 401 | 1 |
| 12 | 张野 | male | 28 | 2016-03-11 | operation | NULL | 10000.13 | 403 | 3 |
| 11 | 格格 | female | 28 | 2017-01-27 | sale | NULL | 4000.33 | 402 | 2 |
| 14 | 程咬银 | female | 18 | 2013-03-11 | operation | NULL | 19000.00 | 403 | 3 |
| 15 | 程咬铜 | male | 18 | 2015-04-11 | operation | NULL | 18000.00 | 403 | 3 |
| 13 | 程咬金 | male | 18 | 1997-03-12 | operation | NULL | 20000.00 | 403 | 3 |
| 10 | 星星 | female | 18 | 2016-05-13 | sale | NULL | 3000.29 | 402 | 2 |
| 9 | 丁丁 | female | 18 | 2011-03-12 | sale | NULL | 1000.37 | 402 | 2 |
| 5 | jinxin | male | 18 | 1900-03-01 | teacher | NULL | 30000.00 | 401 | 1 |
| 4 | jingliyang | female | 18 | 2011-02-11 | teacher | NULL | 9000.00 | 401 | 1 |
| 16 | 程咬铁 | female | 18 | 2014-05-12 | operation | NULL | 17000.00 | 403 | 3 |
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
16 rows in set (0.00 sec)
按多列排序:先按照age升序 排序，如果年龄age相同情况下，年龄分不出胜负情况下 ，则按照id 降序排序
mysql> select * from employee order by age asc,id desc;
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id |
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
| 16 | 程咬铁 | female | 18 | 2014-05-12 | operation | NULL | 17000.00 | 403 | 3 |
| 15 | 程咬铜 | male | 18 | 2015-04-11 | operation | NULL | 18000.00 | 403 | 3 |
| 14 | 程咬银 | female | 18 | 2013-03-11 | operation | NULL | 19000.00 | 403 | 3 |
| 13 | 程咬金 | male | 18 | 1997-03-12 | operation | NULL | 20000.00 | 403 | 3 |
| 10 | 星星 | female | 18 | 2016-05-13 | sale | NULL | 3000.29 | 402 | 2 |
| 9 | 丁丁 | female | 18 | 2011-03-12 | sale | NULL | 1000.37 | 402 | 2 |
| 5 | jinxin | male | 18 | 1900-03-01 | teacher | NULL | 30000.00 | 401 | 1 |
| 4 | jingliyang | female | 18 | 2011-02-11 | teacher | NULL | 9000.00 | 401 | 1 |
| 12 | 张野 | male | 28 | 2016-03-11 | operation | NULL | 10000.13 | 403 | 3 |
| 11 | 格格 | female | 28 | 2017-01-27 | sale | NULL | 4000.33 | 402 | 2 |
| 3 | liwenzhou | male | 28 | 2012-11-01 | teacher | NULL | 2100.00 | 401 | 1 |
| 8 | 丫丫 | female | 38 | 2010-11-01 | sale | NULL | 2000.35 | 402 | 2 |
| 7 | 歪歪 | female | 48 | 2015-03-11 | sale | NULL | 3000.13 | 402 | 2 |
| 6 | 成龙 | male | 48 | 2010-11-11 | teacher | NULL | 10000.00 | 401 | 1 |
| 2 | yuanhao | male | 73 | 2014-07-01 | teacher | NULL | 3500.00 | 401 | 1 |
| 1 | alex | male | 78 | 2015-03-02 | teacher | NULL | 1000000.31 | 401 | 1 |
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
16 rows in set (0.00 sec)
按单列排序
SELECT * FROM employee ORDER BY salary;
SELECT * FROM employee ORDER BY salary ASC;
SELECT * FROM employee ORDER BY salary DESC; 按多列排序:先按照age排序，如果年纪相同，则按照薪资排序
SELECT * from employee
ORDER BY age,
salary DESC;
1. 查询所有员工信息，先按照age升序排序，如果age相同则按照hire_date降序排序
select * from employee order by age,hire_date desc;
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id |
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
| 10 | 星星 | female | 18 | 2016-05-13 | sale | NULL | 3000.29 | 402 | 2 |
| 15 | 程咬铜 | male | 18 | 2015-04-11 | operation | NULL | 18000.00 | 403 | 3 |
| 16 | 程咬铁 | female | 18 | 2014-05-12 | operation | NULL | 17000.00 | 403 | 3 |
| 14 | 程咬银 | female | 18 | 2013-03-11 | operation | NULL | 19000.00 | 403 | 3 |
| 9 | 丁丁 | female | 18 | 2011-03-12 | sale | NULL | 1000.37 | 402 | 2 |
| 4 | jingliyang | female | 18 | 2011-02-11 | teacher | NULL | 9000.00 | 401 | 1 |
| 13 | 程咬金 | male | 18 | 1997-03-12 | operation | NULL | 20000.00 | 403 | 3 |
| 5 | jinxin | male | 18 | 1900-03-01 | teacher | NULL | 30000.00 | 401 | 1 |
| 11 | 格格 | female | 28 | 2017-01-27 | sale | NULL | 4000.33 | 402 | 2 |
| 12 | 张野 | male | 28 | 2016-03-11 | operation | NULL | 10000.13 | 403 | 3 |
| 3 | liwenzhou | male | 28 | 2012-11-01 | teacher | NULL | 2100.00 | 401 | 1 |
| 8 | 丫丫 | female | 38 | 2010-11-01 | sale | NULL | 2000.35 | 402 | 2 |
| 7 | 歪歪 | female | 48 | 2015-03-11 | sale | NULL | 3000.13 | 402 | 2 |
| 6 | 成龙 | male | 48 | 2010-11-11 | teacher | NULL | 10000.00 | 401 | 1 |
| 2 | yuanhao | male | 73 | 2014-07-01 | teacher | NULL | 3500.00 | 401 | 1 |
| 1 | alex | male | 78 | 2015-03-02 | teacher | NULL | 1000000.31 | 401 | 1 |
+----+------------+--------+-----+------------+-----------+--------------+------------+--------+-----------+
16 rows in set (0.00 sec)
2. 查询各岗位平均薪资大于10000的岗位名、平均工资,结果按平均薪资升序排列
mysql> select post,avg(salary) from employee group by post having avg(salary) >10000 order by avg(salary);
+-----------+---------------+
| post | avg(salary) |
+-----------+---------------+
| operation | 16800.026000 |
| teacher | 175766.718333 |
+-----------+---------------+
2 rows in set (0.01 sec)
3. 查询各岗位平均薪资大于10000的岗位名、平均工资,结果按平均薪资降序排列
mysql> select post,avg(salary) from employee group by post having avg(salary) >10000 order by avg(salary) desc;
+-----------+---------------+
| post | avg(salary) |
+-----------+---------------+
| teacher | 175766.718333 |
| operation | 16800.026000 |
+-----------+---------------+
2 rows in set (0.01 sec)