97-98复习连接查询、子查询,子查询经典案例
SQL99语法：
1.内连接
语法：
select 查询列表
from 表1
【inner】(inner可以省略，写不写都表示内连) join 表2 别名
on 连接条件
where 筛选条件
group by 分组列表
having 分组后的筛选
order by 排序列表
limit offset，size;
特点：
-
-
表的顺序可以调换
-
内连接的结果=多表的交集
-
n表连接至少需要n-1个连接条件
-
分类：
等值连接
非等职连接
自连接
2、外连接:
语法：
select 查询列表
from 表1
left|right|full【outer】(outer可以省略) join 表2 别名
on 连接条件
where 筛选条件
group by 分组列表
having 分组后的筛选
order by 排序列表
limit offset，size;
特点：
-
- 查询的结果=主表中所有的行，从表和它匹配的将显示匹配行，如果从表没有匹配的则显示null
- left join左边是主表，right join右边就是主表
- full join 两边都是主表
- 一般用于查询除了交集部分的剩余的不匹配的行
3、交叉连接
语法：
select 查询列表
from 表名1 别名
cross join 表2 别名;
特点：
类似于笛卡尔乘积
子查询
一、含义
嵌套在其他语句内部的select语句称为子查询或内查询，
外面的语句可以是insert、update、delete、select等，一般select作为外面语句较多
外面如果为select语句，则此语句称为外查询或主查询
二、分类
1.按出现的位置
select后面
仅仅支持标量子查询，放别的还不行，会报错
from后面
表子查询
作为条件，出现在where或having后面
标量子查询
列子查询
行子查询
exists后面
标量子查询
列子查询
行子查询
表子查询
2、按结果集的行列
标量子查询(单行子查询):结果集为一行一列
列子查询(多行子查询):结果集为多行一列
行子查询：结果集为多行多列
表子查询(嵌套子查询）：结果集为多行多列
三、示例
where或having后面
1.标量子查询
案例：查询最低工资的员工姓名和工资
(1)最低工资
select min(salary) from employees
(2)查询员工的姓名和工资，要求工资=(1)
select last_name,salary
from employees
where salary=(
select min(salary) from employees
);
2、列子查询
案例：查询所有是领导的员工姓名
(1)查询所有员工的manager_id
select manager_id
from employees;
(2)查询姓名，employee_id属于(1)列表的一个
select last_name
from employees
where employee_id in (
select manager_id
from employees
);
分页查询：
一、应用场景
当要查询的条目数太多，一页显示不全
二、语法
select 查询列表
from 表
limit 【offset】，size;
注意：
offset代表的是起始的条目索引，默认从0开始
size代表的是显示的条目数
公式：
假如要显示的页数为page，每一页条目数为size
select 查询列表
from 表
limit (page-1)*size,size;
子查询经典案例：
1 /* 2 SQLyog Ultimate v10.00 Beta1 3 MySQL - 5.5.15 : Database - myemployees 4 ********************************************************************* 5 */ 6 7 8 /*!40101 SET NAMES utf8 */; 9 10 /*!40101 SET SQL_MODE=''*/; 11 12 /*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */; 13 /*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */; 14 /*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */; 15 /*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */; 16 CREATE DATABASE /*!32312 IF NOT EXISTS*/`myemployees` /*!40100 DEFAULT CHARACTER SET gb2312 */; 17 18 USE `myemployees`; 19 20 /*Table structure for table `departments` */ 21 22 DROP TABLE IF EXISTS `departments`; 23 24 CREATE TABLE `departments` ( 25 `department_id` int(4) NOT NULL AUTO_INCREMENT, 26 `department_name` varchar(3) DEFAULT NULL, 27 `manager_id` int(6) DEFAULT NULL, 28 `location_id` int(4) DEFAULT NULL, 29 PRIMARY KEY (`department_id`), 30 KEY `loc_id_fk` (`location_id`), 31 CONSTRAINT `loc_id_fk` FOREIGN KEY (`location_id`) REFERENCES `locations` (`location_id`) 32 ) ENGINE=InnoDB AUTO_INCREMENT=271 DEFAULT CHARSET=gb2312; 33 34 /*Data for the table `departments` */ 35 36 insert into `departments`(`department_id`,`department_name`,`manager_id`,`location_id`) values (10,'Adm',200,1700),(20,'Mar',201,1800),(30,'Pur',114,1700),(40,'Hum',203,2400),(50,'Shi',121,1500),(60,'IT',103,1400),(70,'Pub',204,2700),(80,'Sal',145,2500),(90,'Exe',100,1700),(100,'Fin',108,1700),(110,'Acc',205,1700),(120,'Tre',NULL,1700),(130,'Cor',NULL,1700),(140,'Con',NULL,1700),(150,'Sha',NULL,1700),(160,'Ben',NULL,1700),(170,'Man',NULL,1700),(180,'Con',NULL,1700),(190,'Con',NULL,1700),(200,'Ope',NULL,1700),(210,'IT ',NULL,1700),(220,'NOC',NULL,1700),(230,'IT ',NULL,1700),(240,'Gov',NULL,1700),(250,'Ret',NULL,1700),(260,'Rec',NULL,1700),(270,'Pay',NULL,1700); 37 38 /*Table structure for table `employees` */ 39 40 DROP TABLE IF EXISTS `employees`; 41 42 CREATE TABLE `employees` ( 43 `employee_id` int(6) NOT NULL AUTO_INCREMENT, 44 `first_name` varchar(20) DEFAULT NULL, 45 `last_name` varchar(25) DEFAULT NULL, 46 `email` varchar(25) DEFAULT NULL, 47 `phone_number` varchar(20) DEFAULT NULL, 48 `job_id` varchar(10) DEFAULT NULL, 49 `salary` double(10,2) DEFAULT NULL, 50 `commission_pct` double(4,2) DEFAULT NULL, 51 `manager_id` int(6) DEFAULT NULL, 52 `department_id` int(4) DEFAULT NULL, 53 `hiredate` datetime DEFAULT NULL, 54 PRIMARY KEY (`employee_id`), 55 KEY `dept_id_fk` (`department_id`), 56 KEY `job_id_fk` (`job_id`), 57 CONSTRAINT `dept_id_fk` FOREIGN KEY (`department_id`) REFERENCES `departments` (`department_id`), 58 CONSTRAINT `job_id_fk` FOREIGN KEY (`job_id`) REFERENCES `jobs` (`job_id`) 59 ) ENGINE=InnoDB AUTO_INCREMENT=207 DEFAULT CHARSET=gb2312; 60 61 /*Data for the table `employees` */ 62 63 insert into `employees`(`employee_id`,`first_name`,`last_name`,`email`,`phone_number`,`job_id`,`salary`,`commission_pct`,`manager_id`,`department_id`,`hiredate`) values (100,'Steven','K_ing','SKING','515.123.4567','AD_PRES',24000.00,NULL,NULL,90,'1992-04-03 00:00:00'),(101,'Neena','Kochhar','NKOCHHAR','515.123.4568','AD_VP',17000.00,NULL,100,90,'1992-04-03 00:00:00'),(102,'Lex','De Haan','LDEHAAN','515.123.4569','AD_VP',17000.00,NULL,100,90,'1992-04-03 00:00:00'),(103,'Alexander','Hunold','AHUNOLD','590.423.4567','IT_PROG',9000.00,NULL,102,60,'1992-04-03 00:00:00'),(104,'Bruce','Ernst','BERNST','590.423.4568','IT_PROG',6000.00,NULL,103,60,'1992-04-03 00:00:00'),(105,'David','Austin','DAUSTIN','590.423.4569','IT_PROG',4800.00,NULL,103,60,'1998-03-03 00:00:00'),(106,'Valli','Pataballa','VPATABAL','590.423.4560','IT_PROG',4800.00,NULL,103,60,'1998-03-03 00:00:00'),(107,'Diana','Lorentz','DLORENTZ','590.423.5567','IT_PROG',4200.00,NULL,103,60,'1998-03-03 00:00:00'),(108,'Nancy','Greenberg','NGREENBE','515.124.4569','FI_MGR',12000.00,NULL,101,100,'1998-03-03 00:00:00'),(109,'Daniel','Faviet','DFAVIET','515.124.4169','FI_ACCOUNT',9000.00,NULL,108,100,'1998-03-03 00:00:00'),(110,'John','Chen','JCHEN','515.124.4269','FI_ACCOUNT',8200.00,NULL,108,100,'2000-09-09 00:00:00'),(111,'Ismael','Sciarra','ISCIARRA','515.124.4369','FI_ACCOUNT',7700.00,NULL,108,100,'2000-09-09 00:00:00'),(112,'Jose Manuel','Urman','JMURMAN','515.124.4469','FI_ACCOUNT',7800.00,NULL,108,100,'2000-09-09 00:00:00'),(113,'Luis','Popp','LPOPP','515.124.4567','FI_ACCOUNT',6900.00,NULL,108,100,'2000-09-09 00:00:00'),(114,'Den','Raphaely','DRAPHEAL','515.127.4561','PU_MAN',11000.00,NULL,100,30,'2000-09-09 00:00:00'),(115,'Alexander','Khoo','AKHOO','515.127.4562','PU_CLERK',3100.00,NULL,114,30,'2000-09-09 00:00:00'),(116,'Shelli','Baida','SBAIDA','515.127.4563','PU_CLERK',2900.00,NULL,114,30,'2000-09-09 00:00:00'),(117,'Sigal','Tobias','STOBIAS','515.127.4564','PU_CLERK',2800.00,NULL,114,30,'2000-09-09 00:00:00'),(118,'Guy','Himuro','GHIMURO','515.127.4565','PU_CLERK',2600.00,NULL,114,30,'2000-09-09 00:00:00'),(119,'Karen','Colmenares','KCOLMENA','515.127.4566','PU_CLERK',2500.00,NULL,114,30,'2000-09-09 00:00:00'),(120,'Matthew','Weiss','MWEISS','650.123.1234','ST_MAN',8000.00,NULL,100,50,'2004-02-06 00:00:00'),(121,'Adam','Fripp','AFRIPP','650.123.2234','ST_MAN',8200.00,NULL,100,50,'2004-02-06 00:00:00'),(122,'Payam','Kaufling','PKAUFLIN','650.123.3234','ST_MAN',7900.00,NULL,100,50,'2004-02-06 00:00:00'),(123,'Shanta','Vollman','SVOLLMAN','650.123.4234','ST_MAN',6500.00,NULL,100,50,'2004-02-06 00:00:00'),(124,'Kevin','Mourgos','KMOURGOS','650.123.5234','ST_MAN',5800.00,NULL,100,50,'2004-02-06 00:00:00'),(125,'Julia','Nayer','JNAYER','650.124.1214','ST_CLERK',3200.00,NULL,120,50,'2004-02-06 00:00:00'),(126,'Irene','Mikkilineni','IMIKKILI','650.124.1224','ST_CLERK',2700.00,NULL,120,50,'2004-02-06 00:00:00'),(127,'James','Landry','JLANDRY','650.124.1334','ST_CLERK',2400.00,NULL,120,50,'2004-02-06 00:00:00'),(128,'Steven','Markle','SMARKLE','650.124.1434','ST_CLERK',2200.00,NULL,120,50,'2004-02-06 00:00:00'),(129,'Laura','Bissot','LBISSOT','650.124.5234','ST_CLERK',3300.00,NULL,121,50,'2004-02-06 00:00:00'),(130,'Mozhe','Atkinson','MATKINSO','650.124.6234','ST_CLERK',2800.00,NULL,121,50,'2004-02-06 00:00:00'),(131,'James','Marlow','JAMRLOW','650.124.7234','ST_CLERK',2500.00,NULL,121,50,'2004-02-06 00:00:00'),(132,'TJ','Olson','TJOLSON','650.124.8234','ST_CLERK',2100.00,NULL,121,50,'2004-02-06 00:00:00'),(133,'Jason','Mallin','JMALLIN','650.127.1934','ST_CLERK',3300.00,NULL,122,50,'2004-02-06 00:00:00'),(134,'Michael','Rogers','MROGERS','650.127.1834','ST_CLERK',2900.00,NULL,122,50,'2002-12-23 00:00:00'),(135,'Ki','Gee','KGEE','650.127.1734','ST_CLERK',2400.00,NULL,122,50,'2002-12-23 00:00:00'),(136,'Hazel','Philtanker','HPHILTAN','650.127.1634','ST_CLERK',2200.00,NULL,122,50,'2002-12-23 00:00:00'),(137,'Renske','Ladwig','RLADWIG','650.121.1234','ST_CLERK',3600.00,NULL,123,50,'2002-12-23 00:00:00'),(138,'Stephen','Stiles','SSTILES','650.121.2034','ST_CLERK',3200.00,NULL,123,50,'2002-12-23 00:00:00'),(139,'John','Seo','JSEO','650.121.2019','ST_CLERK',2700.00,NULL,123,50,'2002-12-23 00:00:00'),(140,'Joshua','Patel','JPATEL','650.121.1834','ST_CLERK',2500.00,NULL,123,50,'2002-12-23 00:00:00'),(141,'Trenna','Rajs','TRAJS','650.121.8009','ST_CLERK',3500.00,NULL,124,50,'2002-12-23 00:00:00'),(142,'Curtis','Davies','CDAVIES','650.121.2994','ST_CLERK',3100.00,NULL,124,50,'2002-12-23 00:00:00'),(143,'Randall','Matos','RMATOS','650.121.2874','ST_CLERK',2600.00,NULL,124,50,'2002-12-23 00:00:00'),(144,'Peter','Vargas','PVARGAS','650.121.2004','ST_CLERK',2500.00,NULL,124,50,'2002-12-23 00:00:00'),(145,'John','Russell','JRUSSEL','011.44.1344.429268','SA_MAN',14000.00,0.40,100,80,'2002-12-23 00:00:00'),(146,'Karen','Partners','KPARTNER','011.44.1344.467268','SA_MAN',13500.00,0.30,100,80,'2002-12-23 00:00:00'),(147,'Alberto','Errazuriz','AERRAZUR','011.44.1344.429278','SA_MAN',12000.00,0.30,100,80,'2002-12-23 00:00:00'),(148,'Gerald','Cambrault','GCAMBRAU','011.44.1344.619268','SA_MAN',11000.00,0.30,100,80,'2002-12-23 00:00:00'),(149,'Eleni','Zlotkey','EZLOTKEY','011.44.1344.429018','SA_MAN',10500.00,0.20,100,80,'2002-12-23 00:00:00'),(150,'Peter','Tucker','PTUCKER','011.44.1344.129268','SA_REP',10000.00,0.30,145,80,'2014-03-05 00:00:00'),(151,'David','Bernstein','DBERNSTE','011.44.1344.345268','SA_REP',9500.00,0.25,145,80,'2014-03-05 00:00:00'),(152,'Peter','Hall','PHALL','011.44.1344.478968','SA_REP',9000.00,0.25,145,80,'2014-03-05 00:00:00'),(153,'Christopher','Olsen','COLSEN','011.44.1344.498718','SA_REP',8000.00,0.20,145,80,'2014-03-05 00:00:00'),(154,'Nanette','Cambrault','NCAMBRAU','011.44.1344.987668','SA_REP',7500.00,0.20,145,80,'2014-03-05 00:00:00'),(155,'Oliver','Tuvault','OTUVAULT','011.44.1344.486508','SA_REP',7000.00,0.15,145,80,'2014-03-05 00:00:00'),(156,'Janette','K_ing','JKING','011.44.1345.429268','SA_REP',10000.00,0.35,146,80,'2014-03-05 00:00:00'),(157,'Patrick','Sully','PSULLY','011.44.1345.929268','SA_REP',9500.00,0.35,146,80,'2014-03-05 00:00:00'),(158,'Allan','McEwen','AMCEWEN','011.44.1345.829268','SA_REP',9000.00,0.35,146,80,'2014-03-05 00:00:00'),(159,'Lindsey','Smith','LSMITH','011.44.1345.729268','SA_REP',8000.00,0.30,146,80,'2014-03-05 00:00:00'),(160,'Louise','Doran','LDORAN','011.44.1345.629268','SA_REP',7500.00,0.30,146,80,'2014-03-05 00:00:00'),(161,'Sarath','Sewall','SSEWALL','011.44.1345.529268','SA_REP',7000.00,0.25,146,80,'2014-03-05 00:00:00'),(162,'Clara','Vishney','CVISHNEY','011.44.1346.129268','SA_REP',10500.00,0.25,147,80,'2014-03-05 00:00:00'),(163,'Danielle','Greene','DGREENE','011.44.1346.229268','SA_REP',9500.00,0.15,147,80,'2014-03-05 00:00:00'),(164,'Mattea','Marvins','MMARVINS','011.44.1346.329268','SA_REP',7200.00,0.10,147,80,'2014-03-05 00:00:00'),(165,'David','Lee','DLEE','011.44.1346.529268','SA_REP',6800.00,0.10,147,80,'2014-03-05 00:00:00'),(166,'Sundar','Ande','SANDE','011.44.1346.629268','SA_REP',6400.00,0.10,147,80,'2014-03-05 00:00:00'),(167,'Amit','Banda','ABANDA','011.44.1346.729268','SA_REP',6200.00,0.10,147,80,'2014-03-05 00:00:00'),(168,'Lisa','Ozer','LOZER','011.44.1343.929268','SA_REP',11500.00,0.25,148,80,'2014-03-05 00:00:00'),(169,'Harrison','Bloom','HBLOOM','011.44.1343.829268','SA_REP',10000.00,0.20,148,80,'2014-03-05 00:00:00'),(170,'Tayler','Fox','TFOX','011.44.1343.729268','SA_REP',9600.00,0.20,148,80,'2014-03-05 00:00:00'),(171,'William','Smith','WSMITH','011.44.1343.629268','SA_REP',7400.00,0.15,148,80,'2014-03-05 00:00:00'),(172,'Elizabeth','Bates','EBATES','011.44.1343.529268','SA_REP',7300.00,0.15,148,80,'2014-03-05 00:00:00'),(173,'Sundita','Kumar','SKUMAR','011.44.1343.329268','SA_REP',6100.00,0.10,148,80,'2014-03-05 00:00:00'),(174,'Ellen','Abel','EABEL','011.44.1644.429267','SA_REP',11000.00,0.30,149,80,'2014-03-05 00:00:00'),(175,'Alyssa','Hutton','AHUTTON','011.44.1644.429266','SA_REP',8800.00,0.25,149,80,'2014-03-05 00:00:00'),(176,'Jonathon','Taylor','JTAYLOR','011.44.1644.429265','SA_REP',8600.00,0.20,149,80,'2014-03-05 00:00:00'),(177,'Jack','Livingston','JLIVINGS','011.44.1644.429264','SA_REP',8400.00,0.20,149,80,'2014-03-05 00:00:00'),(178,'Kimberely','Grant','KGRANT','011.44.1644.429263','SA_REP',7000.00,0.15,149,NULL,'2014-03-05 00:00:00'),(179,'Charles','Johnson','CJOHNSON','011.44.1644.429262','SA_REP',6200.00,0.10,149,80,'2014-03-05 00:00:00'),(180,'Winston','Taylor','WTAYLOR','650.507.9876','SH_CLERK',3200.00,NULL,120,50,'2014-03-05 00:00:00'),(181,'Jean','Fleaur','JFLEAUR','650.507.9877','SH_CLERK',3100.00,NULL,120,50,'2014-03-05 00:00:00'),(182,'Martha','Sullivan','MSULLIVA','650.507.9878','SH_CLERK',2500.00,NULL,120,50,'2014-03-05 00:00:00'),(183,'Girard','Geoni','GGEONI','650.507.9879','SH_CLERK',2800.00,NULL,120,50,'2014-03-05 00:00:00'),(184,'Nandita','Sarchand','NSARCHAN','650.509.1876','SH_CLERK',4200.00,NULL,121,50,'2014-03-05 00:00:00'),(185,'Alexis','Bull','ABULL','650.509.2876','SH_CLERK',4100.00,NULL,121,50,'2014-03-05 00:00:00'),(186,'Julia','Dellinger','JDELLING','650.509.3876','SH_CLERK',3400.00,NULL,121,50,'2014-03-05 00:00:00'),(187,'Anthony','Cabrio','ACABRIO','650.509.4876','SH_CLERK',3000.00,NULL,121,50,'2014-03-05 00:00:00'),(188,'Kelly','Chung','KCHUNG','650.505.1876','SH_CLERK',3800.00,NULL,122,50,'2014-03-05 00:00:00'),(189,'Jennifer','Dilly','JDILLY','650.505.2876','SH_CLERK',3600.00,NULL,122,50,'2014-03-05 00:00:00'),(190,'Timothy','Gates','TGATES','650.505.3876','SH_CLERK',2900.00,NULL,122,50,'2014-03-05 00:00:00'),(191,'Randall','Perkins','RPERKINS','650.505.4876','SH_CLERK',2500.00,NULL,122,50,'2014-03-05 00:00:00'),(192,'Sarah','Bell','SBELL','650.501.1876','SH_CLERK',4000.00,NULL,123,50,'2014-03-05 00:00:00'),(193,'Britney','Everett','BEVERETT','650.501.2876','SH_CLERK',3900.00,NULL,123,50,'2014-03-05 00:00:00'),(194,'Samuel','McCain','SMCCAIN','650.501.3876','SH_CLERK',3200.00,NULL,123,50,'2014-03-05 00:00:00'),(195,'Vance','Jones','VJONES','650.501.4876','SH_CLERK',2800.00,NULL,123,50,'2014-03-05 00:00:00'),(196,'Alana','Walsh','AWALSH','650.507.9811','SH_CLERK',3100.00,NULL,124,50,'2014-03-05 00:00:00'),(197,'Kevin','Feeney','KFEENEY','650.507.9822','SH_CLERK',3000.00,NULL,124,50,'2014-03-05 00:00:00'),(198,'Donald','OConnell','DOCONNEL','650.507.9833','SH_CLERK',2600.00,NULL,124,50,'2014-03-05 00:00:00'),(199,'Douglas','Grant','DGRANT','650.507.9844','SH_CLERK',2600.00,NULL,124,50,'2014-03-05 00:00:00'),(200,'Jennifer','Whalen','JWHALEN','515.123.4444','AD_ASST',4400.00,NULL,101,10,'2016-03-03 00:00:00'),(201,'Michael','Hartstein','MHARTSTE','515.123.5555','MK_MAN',13000.00,NULL,100,20,'2016-03-03 00:00:00'),(202,'Pat','Fay','PFAY','603.123.6666','MK_REP',6000.00,NULL,201,20,'2016-03-03 00:00:00'),(203,'Susan','Mavris','SMAVRIS','515.123.7777','HR_REP',6500.00,NULL,101,40,'2016-03-03 00:00:00'),(204,'Hermann','Baer','HBAER','515.123.8888','PR_REP',10000.00,NULL,101,70,'2016-03-03 00:00:00'),(205,'Shelley','Higgins','SHIGGINS','515.123.8080','AC_MGR',12000.00,NULL,101,110,'2016-03-03 00:00:00'),(206,'William','Gietz','WGIETZ','515.123.8181','AC_ACCOUNT',8300.00,NULL,205,110,'2016-03-03 00:00:00'); 64 65 /*Table structure for table `jobs` */ 66 67 DROP TABLE IF EXISTS `jobs`; 68 69 CREATE TABLE `jobs` ( 70 `job_id` varchar(10) NOT NULL, 71 `job_title` varchar(35) DEFAULT NULL, 72 `min_salary` int(6) DEFAULT NULL, 73 `max_salary` int(6) DEFAULT NULL, 74 PRIMARY KEY (`job_id`) 75 ) ENGINE=InnoDB DEFAULT CHARSET=gb2312; 76 77 /*Data for the table `jobs` */ 78 79 insert into `jobs`(`job_id`,`job_title`,`min_salary`,`max_salary`) values ('AC_ACCOUNT','Public Accountant',4200,9000),('AC_MGR','Accounting Manager',8200,16000),('AD_ASST','Administration Assistant',3000,6000),('AD_PRES','President',20000,40000),('AD_VP','Administration Vice President',15000,30000),('FI_ACCOUNT','Accountant',4200,9000),('FI_MGR','Finance Manager',8200,16000),('HR_REP','Human Resources Representative',4000,9000),('IT_PROG','Programmer',4000,10000),('MK_MAN','Marketing Manager',9000,15000),('MK_REP','Marketing Representative',4000,9000),('PR_REP','Public Relations Representative',4500,10500),('PU_CLERK','Purchasing Clerk',2500,5500),('PU_MAN','Purchasing Manager',8000,15000),('SA_MAN','Sales Manager',10000,20000),('SA_REP','Sales Representative',6000,12000),('SH_CLERK','Shipping Clerk',2500,5500),('ST_CLERK','Stock Clerk',2000,5000),('ST_MAN','Stock Manager',5500,8500); 80 81 /*Table structure for table `locations` */ 82 83 DROP TABLE IF EXISTS `locations`; 84 85 CREATE TABLE `locations` ( 86 `location_id` int(11) NOT NULL AUTO_INCREMENT, 87 `street_address` varchar(40) DEFAULT NULL, 88 `postal_code` varchar(12) DEFAULT NULL, 89 `city` varchar(30) DEFAULT NULL, 90 `state_province` varchar(25) DEFAULT NULL, 91 `country_id` varchar(2) DEFAULT NULL, 92 PRIMARY KEY (`location_id`) 93 ) ENGINE=InnoDB AUTO_INCREMENT=3201 DEFAULT CHARSET=gb2312; 94 95 /*Data for the table `locations` */ 96 97 insert into `locations`(`location_id`,`street_address`,`postal_code`,`city`,`state_province`,`country_id`) values (1000,'1297 Via Cola di Rie','00989','Roma',NULL,'IT'),(1100,'93091 Calle della Testa','10934','Venice',NULL,'IT'),(1200,'2017 Shinjuku-ku','1689','Tokyo','Tokyo Prefecture','JP'),(1300,'9450 Kamiya-cho','6823','Hiroshima',NULL,'JP'),(1400,'2014 Jabberwocky Rd','26192','Southlake','Texas','US'),(1500,'2011 Interiors Blvd','99236','South San Francisco','California','US'),(1600,'2007 Zagora St','50090','South Brunswick','New Jersey','US'),(1700,'2004 Charade Rd','98199','Seattle','Washington','US'),(1800,'147 Spadina Ave','M5V 2L7','Toronto','Ontario','CA'),(1900,'6092 Boxwood St','YSW 9T2','Whitehorse','Yukon','CA'),(2000,'40-5-12 Laogianggen','190518','Beijing',NULL,'CN'),(2100,'1298 Vileparle (E)','490231','Bombay','Maharashtra','IN'),(2200,'12-98 Victoria Street','2901','Sydney','New South Wales','AU'),(2300,'198 Clementi North','540198','Singapore',NULL,'SG'),(2400,'8204 Arthur St',NULL,'London',NULL,'UK'),(2500,'Magdalen Centre, The Oxford Science Park','OX9 9ZB','Oxford','Oxford','UK'),(2600,'9702 Chester Road','09629850293','Stretford','Manchester','UK'),(2700,'Schwanthalerstr. 7031','80925','Munich','Bavaria','DE'),(2800,'Rua Frei Caneca 1360 ','01307-002','Sao Paulo','Sao Paulo','BR'),(2900,'20 Rue des Corps-Saints','1730','Geneva','Geneve','CH'),(3000,'Murtenstrasse 921','3095','Bern','BE','CH'),(3100,'Pieter Breughelstraat 837','3029SK','Utrecht','Utrecht','NL'),(3200,'Mariano Escobedo 9991','11932','Mexico City','Distrito Federal,','MX'); 98 99 /*!40101 SET SQL_MODE=@OLD_SQL_MODE */; 100 /*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */; 101 /*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */; 102 /*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;
1、查询工资最低的员工信息：last_name,salary
#(1)查询最低的工资
select min(salary)
from employees
#(2)查询last_name,salary,要求salary=(1)
select last_name,salary
from employees
where salary = (
select min(salary)
from employees
);
2、查询平均工资最低的部门信息
#方法一：
#(1)各部门的平均工资
select avg(salary),department_id
from employees
group by department_id;
#(2)查询(1)结果上的最低平均工资
select min(ag)
from (
select avg(salary),department_id
from employees
group by department_id
);
#(3)查询哪个部门的平均工资=(2)
select avg(salary),department_id
from employees
group by department_id
having avg(salary)=(
select min(ag)
from (
select avg(salary),department_id
from employees
group by department_id
)
);
#(4)查询部门信息
select d.*
from department d
from d.department_id = (
select avg(salary),department_id
from employees
group by department_id
having avg(salary)=(
select min(ag)
from (
select avg(salary),department_id
from employees
group by department_id
)
)
);
方法二：
#(1)求出平均工资最低的部门编号
select avg(salary),department_id
from employees
group by department_id
order by avg(salary)
limit 1;
#(2)查询部门信息
select *
from departments
where department_id = (
select department_id
from employees
group by department_id
order by avg(salary)
limit 1
);
3、查询平均工资最低的部门信息和该部门的平均工资
select departments.*,ag
from departments
inner join (
select avg(salary) as ag,department_id
from employees
group by department_id
order by avg(salary)
limit 1
) as dep_infom
on departments.department_id = dep_infom.department_id
where departments.department_id = (
select department_id
from employees
group by department_id
order by avg(salary)
limit 1
);
4、查询平均工资最高的job信息
#(1)查询每个job的平均工资
select avg(salary),job_id
from employees
group by job_id;
#(2)查询最高的平均工资与最高工资对应的job_id
select max(ag),job_id
from (
select avg(salary) as ag,job_id
from employees
group by job_id
order by ag desc
) as ag_emp
limit 1;
#(3)查询对应的job信息
select jobs.*
from jobs
inner join (
select max(ag),job_id
from (
select avg(salary) as ag,job_id
from employees
group by job_id
order by ag desc
) as ag_emp
limit 1
);
#或
select *
from jobs
where job_id =(
select job_id
from employees
group by job_id
order by avg(salary)
limit1
);
5、查询平均工资高于公司平均工资的部门有哪些？
#(1)公司的平均工资
select avg(salary)
from employees;
#(2)每个部门的平均工资
select avg(salary),department_id
from employees
group by department_id;
#(3)筛选(2)结果集,满足平均工资>(1)
select avg(salary),department_id
from employees
group by department_id
having avg(salary)>(
select avg(salary)
from employees
);
6、查询出公司中所有manager的详细信息。
#(1)查询所有manager的员工编号
select distinct manager_id
from employee
#(2)查询详细信息，满足manager_id=(1)
select *
from employees
where employee_id = any (
select distinct manager_id
from employees
);
7、各个部门中 最高工资中最低的那个部门的最低工资是多少
#(1)查询各部门的最高工资最低的那个部门
select max(salary),department_id
from employees
group by department_id
order by max(salary) asc
limit 1;
#(2)查询(1)结果的那个部门的最低工资
select min(salary)，department_id
from employees
group by department_id
having department_id = ( # =不能替换为in
| 0 | 8 | 15:30:04 | select min(salary)，department_id from employees group by departmenrt_id having department_id in ( select department_id from employees group by department_id order by max(salary) asc limit 1 ) LIMIT 0, 50000 | Error Code: 1235. This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery' | 0.000 sec |
select department_id
from employees
group by department_id
order by max(salary) asc
limit 1
);
#或
select min(salary),department_id
from employees
where department_id = (
select department_id
from employees
group by department_id
order by max(salary) asc
limit 1
);
8、查询平均工资最高的部门的manager的详细信息：last_name, department_id, email, salary
#(1)平均工资最高的部门编号
select avg(salary),department_id
from employees
group by department_id
order by avg(salary) desc
limit 1;
#(2)将employees和departments连接查询，筛选条件是(1)
select last_name,d.department_id,email,salary
from employees e
inner join departments d
on d.manager_id = e.employee_id
where d.department_id = (
select avg(salary),department_id
from employees
group by department_id
order by avg(salary) desc
limit 1
);
