[TOC]
>[success] ## **一：排序查询：**
<br>
<br>
>[info] ### **1：语法规则：**
select 查询列表
from 表
【where 筛选条件】
order by 排序的字段|表达式|函数|别名 【asc|desc】
特点：
1、**asc**：代表的是升序，desc代表的是降序，如果不写，默认是升序
2、**order by** 子句中可以支持多个字段，多个字段、表达式、函数、别名
3、order by 子句一般是放在查询语句的最后面，limit子句除外
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>[info] ### 2：**准备数据**
```[sql]
CREATE TABLE `gin_employees` (
`employee_id` int(6) NOT NULL AUTO_INCREMENT,
`first_name` varchar(20) DEFAULT NULL,
`last_name` varchar(25) DEFAULT NULL,
`email` varchar(25) DEFAULT NULL,
`phone_number` varchar(20) DEFAULT NULL,
`job_id` varchar(10) DEFAULT NULL,
`salary` double(10,2) DEFAULT NULL,
`commission_pct` double(4,2) DEFAULT NULL,
`manager_id` int(6) DEFAULT NULL,
`department_id` int(4) DEFAULT NULL,
`hiredate` datetime DEFAULT NULL,
PRIMARY KEY (`employee_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
```
```sql
CREATE TABLE `gin_employees` (
`employee_id` int(6) NOT NULL AUTO_INCREMENT,
`first_name` varchar(20) DEFAULT NULL,
`last_name` varchar(25) DEFAULT NULL,
`email` varchar(25) DEFAULT NULL,
`phone_number` varchar(20) DEFAULT NULL,
`job_id` varchar(10) DEFAULT NULL,
`salary` double(10,2) DEFAULT NULL,
`commission_pct` double(4,2) DEFAULT NULL,
`manager_id` int(6) DEFAULT NULL,
`department_id` int(4) DEFAULT NULL,
`hiredate` datetime DEFAULT NULL,
PRIMARY KEY (`employee_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
```
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>[info]### 3：**插入数据**
```sql
INSERT INTO gin_employees VALUES ('100', 'Steven', 'K_ing', 'SKING', '515.123.4567', 'AD_PRES', '24000.00', null, null, '90', '1992-04-03 00:00:00');
INSERT INTO gin_employees VALUES ('101', 'Neena', 'Kochhar', 'NKOCHHAR', '515.123.4568', 'AD_VP', '17000.00', null, '100', '90', '1992-04-03 00:00:00');
INSERT INTO gin_employees VALUES ('102', 'Lex', 'De Haan', 'LDEHAAN', '515.123.4569', 'AD_VP', '17000.00', null, '100', '90', '1992-04-03 00:00:00');
INSERT INTO gin_employees VALUES ('103', 'Alexander', 'Hunold', 'AHUNOLD', '590.423.4567', 'IT_PROG', '9000.00', null, '102', '60', '1992-04-03 00:00:00');
INSERT INTO gin_employees VALUES ('104', 'Bruce', 'Ernst', 'BERNST', '590.423.4568', 'IT_PROG', '6000.00', null, '103', '60', '1992-04-03 00:00:00');
INSERT INTO gin_employees VALUES ('105', 'David', 'Austin', 'DAUSTIN', '590.423.4569', 'IT_PROG', '4800.00', null, '103', '60', '1998-03-03 00:00:00');
INSERT INTO gin_employees VALUES ('106', 'Valli', 'Pataballa', 'VPATABAL', '590.423.4560', 'IT_PROG', '4800.00', null, '103', '60', '1998-03-03 00:00:00');
INSERT INTO gin_employees VALUES ('107', 'Diana', 'Lorentz', 'DLORENTZ', '590.423.5567', 'IT_PROG', '4200.00', null, '103', '60', '1998-03-03 00:00:00');
INSERT INTO gin_employees VALUES ('108', 'Nancy', 'Greenberg', 'NGREENBE', '515.124.4569', 'FI_MGR', '12000.00', null, '101', '100', '1998-03-03 00:00:00');
INSERT INTO gin_employees VALUES ('109', 'Daniel', 'Faviet', 'DFAVIET', '515.124.4169', 'FI_ACCOUNT', '9000.00', null, '108', '100', '1998-03-03 00:00:00');
INSERT INTO gin_employees VALUES ('110', 'John', 'Chen', 'JCHEN', '515.124.4269', 'FI_ACCOUNT', '8200.00', null, '108', '100', '2000-09-09 00:00:00');
INSERT INTO gin_employees VALUES ('111', 'Ismael', 'Sciarra', 'ISCIARRA', '515.124.4369', 'FI_ACCOUNT', '7700.00', null, '108', '100', '2000-09-09 00:00:00');
INSERT INTO gin_employees VALUES ('112', 'Jose Manuel', 'Urman', 'JMURMAN', '515.124.4469', 'FI_ACCOUNT', '7800.00', null, '108', '100', '2000-09-09 00:00:00');
INSERT INTO gin_employees VALUES ('113', 'Luis', 'Popp', 'LPOPP', '515.124.4567', 'FI_ACCOUNT', '6900.00', null, '108', '100', '2000-09-09 00:00:00');
INSERT INTO gin_employees VALUES ('114', 'Den', 'Raphaely', 'DRAPHEAL', '515.127.4561', 'PU_MAN', '11000.00', null, '100', '30', '2000-09-09 00:00:00');
INSERT INTO gin_employees VALUES ('115', 'Alexander', 'Khoo', 'AKHOO', '515.127.4562', 'PU_CLERK', '3100.00', null, '114', '30', '2000-09-09 00:00:00');
INSERT INTO gin_employees VALUES ('116', 'Shelli', 'Baida', 'SBAIDA', '515.127.4563', 'PU_CLERK', '2900.00', null, '114', '30', '2000-09-09 00:00:00');
INSERT INTO gin_employees VALUES ('117', 'Sigal', 'Tobias', 'STOBIAS', '515.127.4564', 'PU_CLERK', '2800.00', null, '114', '30', '2000-09-09 00:00:00');
INSERT INTO gin_employees VALUES ('118', 'Guy', 'Himuro', 'GHIMURO', '515.127.4565', 'PU_CLERK', '2600.00', null, '114', '30', '2000-09-09 00:00:00');
INSERT INTO gin_employees VALUES ('119', 'Karen', 'Colmenares', 'KCOLMENA', '515.127.4566', 'PU_CLERK', '2500.00', null, '114', '30', '2000-09-09 00:00:00');
INSERT INTO gin_employees VALUES ('120', 'Matthew', 'Weiss', 'MWEISS', '650.123.1234', 'ST_MAN', '8000.00', null, '100', '50', '2004-02-06 00:00:00');
INSERT INTO gin_employees VALUES ('121', 'Adam', 'Fripp', 'AFRIPP', '650.123.2234', 'ST_MAN', '8200.00', null, '100', '50', '2004-02-06 00:00:00');
INSERT INTO gin_employees VALUES ('122', 'Payam', 'Kaufling', 'PKAUFLIN', '650.123.3234', 'ST_MAN', '7900.00', null, '100', '50', '2004-02-06 00:00:00');
INSERT INTO gin_employees VALUES ('123', 'Shanta', 'Vollman', 'SVOLLMAN', '650.123.4234', 'ST_MAN', '6500.00', null, '100', '50', '2004-02-06 00:00:00');
INSERT INTO gin_employees VALUES ('124', 'Kevin', 'Mourgos', 'KMOURGOS', '650.123.5234', 'ST_MAN', '5800.00', null, '100', '50', '2004-02-06 00:00:00');
INSERT INTO gin_employees VALUES ('125', 'Julia', 'Nayer', 'JNAYER', '650.124.1214', 'ST_CLERK', '3200.00', null, '120', '50', '2004-02-06 00:00:00');
INSERT INTO gin_employees VALUES ('126', 'Irene', 'Mikkilineni', 'IMIKKILI', '650.124.1224', 'ST_CLERK', '2700.00', null, '120', '50', '2004-02-06 00:00:00');
INSERT INTO gin_employees VALUES ('127', 'James', 'Landry', 'JLANDRY', '650.124.1334', 'ST_CLERK', '2400.00', null, '120', '50', '2004-02-06 00:00:00');
INSERT INTO gin_employees VALUES ('128', 'Steven', 'Markle', 'SMARKLE', '650.124.1434', 'ST_CLERK', '2200.00', null, '120', '50', '2004-02-06 00:00:00');
INSERT INTO gin_employees VALUES ('129', 'Laura', 'Bissot', 'LBISSOT', '650.124.5234', 'ST_CLERK', '3300.00', null, '121', '50', '2004-02-06 00:00:00');
INSERT INTO gin_employees VALUES ('130', 'Mozhe', 'Atkinson', 'MATKINSO', '650.124.6234', 'ST_CLERK', '2800.00', null, '121', '50', '2004-02-06 00:00:00');
INSERT INTO gin_employees VALUES ('131', 'James', 'Marlow', 'JAMRLOW', '650.124.7234', 'ST_CLERK', '2500.00', null, '121', '50', '2004-02-06 00:00:00');
INSERT INTO gin_employees VALUES ('132', 'TJ', 'Olson', 'TJOLSON', '650.124.8234', 'ST_CLERK', '2100.00', null, '121', '50', '2004-02-06 00:00:00');
INSERT INTO gin_employees VALUES ('133', 'Jason', 'Mallin', 'JMALLIN', '650.127.1934', 'ST_CLERK', '3300.00', null, '122', '50', '2004-02-06 00:00:00');
INSERT INTO gin_employees VALUES ('134', 'Michael', 'Rogers', 'MROGERS', '650.127.1834', 'ST_CLERK', '2900.00', null, '122', '50', '2002-12-23 00:00:00');
INSERT INTO gin_employees VALUES ('135', 'Ki', 'Gee', 'KGEE', '650.127.1734', 'ST_CLERK', '2400.00', null, '122', '50', '2002-12-23 00:00:00');
INSERT INTO gin_employees VALUES ('136', 'Hazel', 'Philtanker', 'HPHILTAN', '650.127.1634', 'ST_CLERK', '2200.00', null, '122', '50', '2002-12-23 00:00:00');
INSERT INTO gin_employees VALUES ('137', 'Renske', 'Ladwig', 'RLADWIG', '650.121.1234', 'ST_CLERK', '3600.00', null, '123', '50', '2002-12-23 00:00:00');
INSERT INTO gin_employees VALUES ('138', 'Stephen', 'Stiles', 'SSTILES', '650.121.2034', 'ST_CLERK', '3200.00', null, '123', '50', '2002-12-23 00:00:00');
INSERT INTO gin_employees VALUES ('139', 'John', 'Seo', 'JSEO', '650.121.2019', 'ST_CLERK', '2700.00', null, '123', '50', '2002-12-23 00:00:00');
INSERT INTO gin_employees VALUES ('140', 'Joshua', 'Patel', 'JPATEL', '650.121.1834', 'ST_CLERK', '2500.00', null, '123', '50', '2002-12-23 00:00:00');
INSERT INTO gin_employees VALUES ('171', 'William', 'Smith', 'WSMITH', '011.44.1343.629268', 'SA_REP', '7400.00', '0.15', '148', '80', '2014-03-05 00:00:00');
INSERT INTO gin_employees VALUES ('172', 'Elizabeth', 'Bates', 'EBATES', '011.44.1343.529268', 'SA_REP', '7300.00', '0.15', '148', '80', '2014-03-05 00:00:00');
INSERT INTO gin_employees VALUES ('173', 'Sundita', 'Kumar', 'SKUMAR', '011.44.1343.329268', 'SA_REP', '6100.00', '0.10', '148', '80', '2014-03-05 00:00:00');
INSERT INTO gin_employees VALUES ('201', 'Michael', 'Hartstein', 'MHARTSTE', '515.123.5555', 'MK_MAN', '13000.00', null, '100', '20', '2016-03-03 00:00:00');
INSERT INTO gin_employees VALUES ('202', 'Pat', 'Fay', 'PFAY', '603.123.6666', 'MK_REP', '6000.00', null, '201', '20', '2016-03-03 00:00:00');
INSERT INTO gin_employees VALUES ('203', 'Susan', 'Mavris', 'SMAVRIS', '515.123.7777', 'HR_REP', '6500.00', null, '101', '40', '2016-03-03 00:00:00');
INSERT INTO gin_employees VALUES ('204', 'Hermann', 'Baer', 'HBAER', '515.123.8888', 'PR_REP', '10000.00', null, '101', '70', '2016-03-03 00:00:00');
INSERT INTO gin_employees VALUES ('205', 'Shelley', 'Higgins', 'SHIGGINS', '515.123.8080', 'AC_MGR', '12000.00', null, '101', '110', '2016-03-03 00:00:00');
INSERT INTO gin_employees VALUES ('206', 'William', 'Gietz', 'WGIETZ', '515.123.8181', 'AC_ACCOUNT', '8300.00', null, '205', '110', '2016-03-03 00:00:00');
```
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>[warning] **需求1：**
查询员工信息，要求工资从高到低排序
```sql
SELECT
*
FROM
gin_employees
ORDER BY
salary DESC;
```
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<br>
>[warning] **需求2：**
查询部门编号>= 90的员工信息，按入职时间的先后进行排序
```sql
SELECT
*
FROM
gin_employees
WHERE
employee_id >= 120
ORDER BY
hiredate ASC;
```
结果：
:-: 
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<br>
>[warning] **需求3：按表达式排序】**
按照年薪的高低显示员工的信息和年薪【按表达式排序】
```sql
SELECT
*,
salary * 12 * (
1 + IFNULL( commission_pct, 0 ))
FROM
gin_employees
ORDER BY
salary * 12 * (
1 + IFNULL( commission_pct, 0 )) DESC;
```
**简化写法：**
```sql
SELECT
*,
salary * 12 * (
1 + IFNULL( commission_pct, 0 )) AS 年薪
FROM
gin_employees
ORDER BY
年薪 DESC;
```
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<br>
>[warning] **需求4：【按函数排序】**
按姓名的长度显示员工的姓名和工资【按函数排序】
LENGTH
```sql
SELECT
LENGTH( first_name ) 字节长度,
last_name,
salary
FROM
gin_employees
ORDER BY
LENGTH( first_name ) DESC;
```
<br>
<br>
>[warning] **需求5：【按多个字段排序】**
查询员工信息，要求先按工资升序，在按员工编号降序
```sql
SELECT
*
FROM
gin_employees
ORDER BY
salary ASC,
employee_id DESC;
```
