ORACLE自带的人力资源（HR）实例数据，本文所用表结构如下：
表名：REGIONS
| 序号 | 列名 | 数据类型 | 长度 | 小数位 | 标识 | 主键 | 允许空 | 默认值 | 说明 |
| 1 | REGION_ID | NUMBER | | | | 是 | 否 | | |
| 2 | REGION_NAME | VARCHAR2 | 25 | | | | 是 | | |
表名：COUNTRIES
| 序号 | 列名 | 数据类型 | 长度 | 小数位 | 标识 | 主键 | 允许空 | 默认值 | 说明 |
| 1 | COUNTRY_ID | CHAR | 2 | | | 是 | 否 | | |
| 2 | COUNTRY_NAME | VARCHAR2 | 40 | | | | 是 | | |
| 3 | REGION_ID | NUMBER | | | | | 是 | | |
表名：LOCATIONS
| 序号 | 列名 | 数据类型 | 长度 | 小数位 | 标识 | 主键 | 允许空 | 默认值 | 说明 |
| 1 | LOCATION_ID | NUMBER | 4 | 0 | | 是 | 否 | | |
| 2 | STREET_ADDRESS | VARCHAR2 | 40 | | | | 是 | | |
| 3 | POSTAL_CODE | VARCHAR2 | 12 | | | | 是 | | |
| 4 | CITY | VARCHAR2 | 30 | | | | 否 | | |
| 5 | STATE_PROVINCE | VARCHAR2 | 25 | | | | 是 | | |
| 6 | COUNTRY_ID | CHAR | 2 | | | | 是 | | |
表名：DEPARTMENTS
| 序号 | 列名 | 数据类型 | 长度 | 小数位 | 标识 | 主键 | 允许空 | 默认值 | 说明 |
| 1 | DEPARTMENT_ID | NUMBER | 4 | 0 | | 是 | 否 | | |
| 2 | DEPARTMENT_NAME | VARCHAR2 | 30 | | | | 否 | | |
| 3 | MANAGER_ID | NUMBER | 6 | 0 | | | 是 | | |
| 4 | LOCATION_ID | NUMBER | 4 | 0 | | | 是 | | |
表名：JOBS
| 序号 | 列名 | 数据类型 | 长度 | 小数位 | 标识 | 主键 | 允许空 | 默认值 | 说明 |
| 1 | JOB_ID | VARCHAR2 | 10 | | | 是 | 否 | | |
| 2 | JOB_TITLE | VARCHAR2 | 35 | | | | 否 | | |
| 3 | MIN_SALARY | NUMBER | 6 | 0 | | | 是 | | |
| 4 | MAX_SALARY | NUMBER | 6 | 0 | | | 是 | | |
表名：EMPLOYEES
| 序号 | 列名 | 数据类型 | 长度 | 小数位 | 标识 | 主键 | 允许空 | 默认值 | 说明 |
| 1 | EMPLOYEE_ID | NUMBER | 6 | 0 | | 是 | 否 | | |
| 2 | FIRST_NAME | VARCHAR2 | 20 | | | | 是 | | |
| 3 | LAST_NAME | VARCHAR2 | 25 | | | | 否 | | |
| 4 | EMAIL | VARCHAR2 | 25 | | | | 否 | | |
| 5 | PHONE_NUMBER | VARCHAR2 | 20 | | | | 是 | | |
| 6 | HIRE_DATE | DATE | 7 | | | | 否 | | |
| 7 | JOB_ID | VARCHAR2 | 10 | | | | 否 | | |
| 8 | SALARY | NUMBER | 8 | 2 | | | 是 | | |
| 9 | COMMISSION_PCT | NUMBER | 2 | 2 | | | 是 | | |
| 10 | MANAGER_ID | NUMBER | 6 | 0 | | | 是 | | |
| 11 | DEPARTMENT_ID | NUMBER | 4 | 0 | | | 是 | | |
ER图：
用SQL完成以下问题列表：
1. 哪些部门的人数比90 号部门的人数多。
2. Den(FIRST_NAME)、Raphaely(LAST_NAME)的领导是谁（非关联子查询）。
3. Den(FIRST_NAME)、Raphaely(LAST_NAME) 领导谁（非关联子查询）。
4. Den(FIRST_NAME)、Raphaely(LAST_NAME) 的领导是谁（关联子查询）。
5. Den(FIRST_NAME)、Raphaely(LAST_NAME) 领导谁（关联子查询）。
6. 列出在同一部门共事，入职日期晚但工资高于其他同事的员工：名字、工资、入职日期
（关联子查询）。
7. 哪些员工跟Den(FIRST_NAME)、Raphaely(LAST_NAME)不在同一个部门（非关联子查询）。
8. 哪些员工跟Den(FIRST_NAME)、Raphaely(LAST_NAME)不在同一个部门（关联子查询）。
9. Finance部门有哪些职位（非关联子查询）。
10. Finance部门有哪些职位（关联子查询）。
/*--------1、哪些部门的人数比90号部门的人数多。---------*/
SQL> SELECT DEPARTMENT_ID,COUNT(*) FROM EMPLOYEES
2 GROUP BY DEPARTMENT_ID
3 HAVING COUNT(*) >
4 (SELECT COUNT(*) FROM EMPLOYEES
5 WHERE DEPARTMENT_ID = 90
6 );
DEPARTMENT_ID COUNT(*)
------------- ----------
30 6
50 45
60 5
80 34
100 6
/*-------2、Den(FIRST_NAME)、Raphaely(LAST_NAME)的
领导是谁（非关联子查询）。---------*/
SQL> SELECT FIRST_NAME || ' ' || LAST_NAME
2 FROM EMPLOYEES
3 WHERE EMPLOYEE_ID =
4 (SELECT MANAGER_ID FROM EMPLOYEES
5 WHERE FIRST_NAME = 'Den'
6 AND LAST_NAME = 'Raphaely'
7 );
FIRST_NAME||''||LAST_NAME
----------------------------------------------
Steven King
/*-------3、Den(FIRST_NAME)、Raphaely(LAST_NAME)领导谁（非关联子查询）。---------*/
SQL> SELECT FIRST_NAME || ' ' || LAST_NAME
2 FROM EMPLOYEES
3 WHERE MANAGER_ID IN
4 (SELECT EMPLOYEE_ID FROM EMPLOYEES
5 WHERE FIRST_NAME = 'Den'
6 AND LAST_NAME = 'Raphaely'
7 );
FIRST_NAME||''||LAST_NAME
----------------------------------------------
Alexander Khoo
Shelli Baida
Sigal Tobias
Guy Himuro
Karen Colmenares
--或者
SQL> SELECT FIRST_NAME || ' ' || LAST_NAME
2 FROM EMPLOYEES
3 WHERE MANAGER_ID =
4 (SELECT EMPLOYEE_ID FROM EMPLOYEES
5 WHERE FIRST_NAME = 'Den'
6 AND LAST_NAME = 'Raphaely'
7 );
FIRST_NAME||''||LAST_NAME
----------------------------------------------
Alexander Khoo
Shelli Baida
Sigal Tobias
Guy Himuro
Karen Colmenares
/*-------4、Den(FIRST_NAME)、Raphaely(LAST_NAME)的领导是谁（关联子查询）。---------*/
SQL> SELECT FIRST_NAME || ' ' || LAST_NAME
2 FROM EMPLOYEES EMP1
3 WHERE EXISTS (
4 SELECT 1 FROM EMPLOYEES EMP2
5 WHERE FIRST_NAME = 'Den'
6 AND LAST_NAME = 'Raphaely'
7 AND EMP2.MANAGER_ID = EMP1.EMPLOYEE_ID);
FIRST_NAME||''||LAST_NAME
----------------------------------------------
Steven King
/*-------5、Den(FIRST_NAME)、Raphaely(LAST_NAME)领导谁（关联子查询）。---------*/
SQL> SELECT FIRST_NAME || ' ' || LAST_NAME
2 FROM EMPLOYEES EMP1
3 WHERE EXISTS (
4 SELECT 1 FROM EMPLOYEES EMP2
5 WHERE FIRST_NAME = 'Den'
6 AND LAST_NAME = 'Raphaely'
7 AND EMP2.EMPLOYEE_ID = EMP1.MANAGER_ID);
FIRST_NAME||''||LAST_NAME
----------------------------------------------
Alexander Khoo
Shelli Baida
Sigal Tobias
Guy Himuro
Karen Colmenares
/*-------6、列出在同一部门共事，入职日期晚但工资高于其他同事的员工：
名字、工资、入职日期（关联子查询）。---------*/
SQL> SELECT FIRST_NAME || ' ' || LAST_NAME AS 姓名,
2 SALARY AS 工资,HIRE_DATE AS 入职日期
3 FROM EMPLOYEES EMP1
4 WHERE EXISTS (
5 SELECT 1 FROM EMPLOYEES EMP2
6 WHERE EMP2.DEPARTMENT_ID = EMP1.DEPARTMENT_ID
7 AND EMP1.HIRE_DATE > EMP2.HIRE_DATE
8 AND EMP1.SALARY > EMP2.SALARY
9 );
姓名 工资 入职日期
---------------------------------------------- ---------- -----------
Nancy Greenberg 12000.00 1994-8-17
Jose Manuel Urman 7800.00 1998-3-7
Shelli Baida 2900.00 1997-12-24
Adam Fripp 8200.00 1997-4-10
Matthew Weiss 8000.00 1996-7-18
Jennifer Dilly 3600.00 1997-8-13
Julia Dellinger 3400.00 1998-6-24
Laura Bissot 3300.00 1997-8-20
Kevin Mourgos 5800.00 1999-11-16
Shanta Vollman 6500.00 1997-10-10
Vance Jones 2800.00 1999-3-17
Anthony Cabrio 3000.00 1999-2-7
Girard Geoni 2800.00 2000-2-3
Douglas Grant 2600.00 2000-1-13
Donald OConnell 2600.00 1999-6-21
Randall Perkins 2500.00 1999-12-19
Martha Sullivan 2500.00 1999-6-21
Kevin Feeney 3000.00 1998-5-23
Alana Walsh 3100.00 1998-4-24
Samuel McCain 3200.00 1998-7-1
Timothy Gates 2900.00 1998-7-11
Jean Fleaur 3100.00 1998-2-23
Winston Taylor 3200.00 1998-1-24
Michael Rogers 2900.00 1998-8-26
Britney Everett 3900.00 1997-3-3
Kelly Chung 3800.00 1997-6-14
Alexis Bull 4100.00 1997-2-20
Randall Matos 2600.00 1998-3-15
John Seo 2700.00 1998-2-12
Stephen Stiles 3200.00 1997-10-26
Mozhe Atkinson 2800.00 1997-10-30
Irene Mikkilineni 2700.00 1998-9-28
Julia Nayer 3200.00 1997-7-16
Hazel Philtanker 2200.00 2000-2-6
Ki Gee 2400.00 1999-12-12
Steven Markle 2200.00 2000-3-8
Sarah Bell 4000.00 1996-2-4
Nandita Sarchand 4200.00 1996-1-27
Lisa Ozer 11500.00 1997-3-11
Clara Vishney 10500.00 1997-11-11
Eleni Zlotkey 10500.00 2000-1-29
Gerald Cambrault 11000.00 1999-10-15
Alberto Errazuriz 12000.00 1997-3-10
Tayler Fox 9600.00 1998-1-24
Harrison Bloom 10000.00 1998-3-23
Danielle Greene 9500.00 1999-3-19
Charles Johnson 7211.00 2000-1-4
Mattea Marvins 7200.00 2000-1-24
Ellen Abel 11000.00 1996-5-11
Karen Partners 13500.00 1997-1-5
John Russell 14000.00 1996-10-1
Peter Tucker 10000.00 1997-1-30
David Bernstein 9500.00 1997-3-24
Jonathon Taylor 8600.00 1998-3-24
Alyssa Hutton 8800.00 1997-3-19
Peter Hall 9000.00 1997-8-20
Jack Livingston 8000.00 1998-4-23
Christopher Olsen 8000.00 1998-3-30
Elizabeth Bates 7300.00 1999-3-24
William Smith 7400.00 1999-2-23
Nanette Cambrault 7500.00 1998-12-9
61 rows selected
/*-------7、哪些员工跟Den(FIRST_NAME)、Raphaely(LAST_NAME)
不在同一个部门（非关联子查询）。---------*/
SQL> SELECT FIRST_NAME || ' ' || LAST_NAME
2 FROM EMPLOYEES
3 WHERE DEPARTMENT_ID <>
4 (SELECT DEPARTMENT_ID FROM EMPLOYEES
5 WHERE FIRST_NAME = 'Den'
6 AND LAST_NAME = 'Raphaely'
7 );
FIRST_NAME||''||LAST_NAME
----------------------------------------------
Steven King
Neena Kochhar
Lex De Haan
Alexander Hunold
Bruce Ernst
David Austin
Valli Pataballa
--等等
--或者
SQL> SELECT FIRST_NAME || ' ' || LAST_NAME
2 FROM EMPLOYEES
3 WHERE DEPARTMENT_ID NOT IN
4 (SELECT DEPARTMENT_ID FROM EMPLOYEES
5 WHERE FIRST_NAME = 'Den'
6 AND LAST_NAME = 'Raphaely'
7 );
/*-------8、哪些员工跟Den(FIRST_NAME)、Raphaely(LAST_NAME)
不在同一个部门（关联子查询）。---------*/
SQL> SELECT FIRST_NAME || ' ' || LAST_NAME
2 FROM EMPLOYEES EMP1
3 WHERE NOT EXISTS (
4 SELECT 1 FROM EMPLOYEES EMP2
5 WHERE EMP1.DEPARTMENT_ID = EMP2.DEPARTMENT_ID
6 AND EMP2.FIRST_NAME = 'Den'
7 AND EMP2.LAST_NAME = 'Raphaely');
FIRST_NAME||''||LAST_NAME
----------------------------------------------
Kimberely Grant
Lex De Haan
Neena Kochhar
Steven King
Pat Fay
Michael Hartstein
Diana Lorentz
Valli Pataballa
--等等
/*-------9、Finance部门有哪些职位（非关联子查询）。---------*/
SQL> SELECT DISTINCT JOB_ID FROM EMPLOYEES
2 WHERE DEPARTMENT_ID = (
3 SELECT DEPARTMENT_ID FROM DEPARTMENTS
4 WHERE DEPARTMENT_NAME = 'Finance');
JOB_ID
----------
FI_ACCOUNT
FI_MGR
--或者
SQL> SELECT DISTINCT JOB_ID FROM EMPLOYEES
2 WHERE DEPARTMENT_ID IN (
3 SELECT DEPARTMENT_ID FROM DEPARTMENTS
4 WHERE DEPARTMENT_NAME = 'Finance');
JOB_ID
----------
FI_ACCOUNT
FI_MGR
/*-------10、Finance部门有哪些职位（关联子查询）。---------*/
SQL> SELECT DISTINCT JOB_ID FROM EMPLOYEES
2 WHERE EXISTS(
3 SELECT 1 FROM DEPARTMENTS
4 WHERE EMPLOYEES.DEPARTMENT_ID = DEPARTMENTS.DEPARTMENT_ID
5 AND DEPARTMENTS.DEPARTMENT_NAME = 'Finance');
JOB_ID
----------
FI_ACCOUNT
FI_MGR