Oracle SQL：经典查询练手第四篇

本文与大家共同讨论与分享ORACLE SQL的一些常用经典查询，欢迎大家补充，同时你认为有那些经典的也可分享出来。在本文中，对每一个问题，你要是认为有什么更好的解决方法也欢迎你及时提出。交流与分享才能共同进步嘛，感谢!

接上三篇:

Oracle SQL：经典查询练手第一篇

Oracle SQL：经典查询练手第二篇

Oracle SQL：经典查询练手第三篇

本篇数据查询属于复杂业务，难度比较高，请继续努力，通过我为大家设立的这个系列，循序渐进，只要你对每一篇，每一个试题都实践测试，认真练习。我相信你对常用、经典的、复杂的SQL已能熟能生巧，信手拈来!

本文使用ORACLE自带的人力资源（HR）实例数据，本文所用表结构如下：

ER图：

用SQL完成以下问题列表：

/*---------------------------------------------  
1. 各个部门平均、最大、最小工资、人数，按照部门号升序排列。  
2. 各个部门中工资大于5000的员工人数。  
3. 各个部门平均工资和人数，按照部门名字升序排列。  
4. 列出每个部门中有同样工资的员工的统计信息，列出他们的部门号，工资，人数。  
5. 列出同部门中工资高于1000 的员工数量超过2 人的部门，显示部门名字、地区名称。  
6. 哪些员工的工资，高于整个公司的平均工资，列出员工的名字和工资（降序）。  
7. 哪些员工的工资，介于50号 和80号部门平均工资之间。  
8. 所在部门平均工资高于5000 的员工名字。  
9. 列出各个部门中工资最高的员工的信息：名字、部门号、工资。  
10. 最高的部门平均工资是多少。  
---------------------------------------------*/ 

#p#

各试题解答如下(欢迎大家指出不同的方法或建议!)：

/*--------1、各个部门平均、最大、最小工资、人数，按照部门号升序排列。---------*/  
SQL> SELECT DEPARTMENT_ID AS 部门号,AVG(SALARY) AS 平均工资  
  2         ,MAX(SALARY) AS 最高工资,MIN(SALARY)  AS 最低工资  
  3         ,COUNT(*) AS 人数  
  4  FROM EMPLOYEES  
  5  GROUP BY DEPARTMENT_ID  
  6  ORDER BY DEPARTMENT_ID ASC;  
   
   部门号       平均工资       最高工资       最低工资         人数  
------         ----------         ----------         ----------         ----------  
       10           4400               4400               4400                 1  
    20          9500              13000           6000                  2  
    30           4150              11000           2500                  6  
    40           6500               6500               6500                  1  
    50             3475.55555     8200               2100                 45  
    60           5760               9000               4200                  5  
    70          10000              10000              10000                  1  
    80             8973.85294     14000           6100                 34  
    90             21333.3333     24000              20000                  3  
   100           8600              12000           6900                  6  
   110          10150              12000           8300                  2  
                7000               7000               7000                  1  
   
12 rows selected  
 
/*--------2、各个部门中工资大于5000的员工人数。---------*/  
SQL> SELECT DEPARTMENT_ID,COUNT(*) FROM EMPLOYEES  
   2  WHERE SALARY > 5000  
   3  GROUP BY DEPARTMENT_ID;  
   
DEPARTMENT_ID   COUNT(*)  
------------- ----------  
           20          2  
           30          1  
           40          1  
           50          5  
           60          2  
           70          1  
           80         34  
           90          3  
          100          6  
          110          2  
                       1  
   
11 rows selected  
 
/*--------3、各个部门平均工资和人数，按照部门名字升序排列。---------*/  
 
SQL> SELECT DPTNAME,AVG(SALARY),COUNT(*) FROM 
  2         (SELECT 
  3             (SELECT DEPT.DEPARTMENT_NAME FROM DEPARTMENTS DEPT  
  4             WHERE DEPT.DEPARTMENT_ID = EMP.DEPARTMENT_ID) DPTNAME,  
  5             EMP.SALARY  
  6  FROM EMPLOYEES EMP)  
  7  GROUP BY DPTNAME  
  8  ORDER BY DPTNAME;  
   
DPTNAME                        AVG(SALARY)   COUNT(*)  
------------------------------ ----------- ----------  
Accounting                           10150          2  
Administration                        4400          1  
Executive                      21333.33333          3  
Finance                               8600          6  
Human Resources                       6500          1  
IT                                    5760          5  
Marketing                             9500          2  
Public Relations                     10000          1  
Purchasing                            4150          6  
Sales                          8973.852941         34  
Shipping                       3475.555555         45  
                                      7000          1   
12 rows selected  
 
--或者--  
 
SQL> SELECT DEPT.DEPARTMENT_NAME,AVG(EMP.SALARY),COUNT(*)  
   2  FROM EMPLOYEES EMP,DEPARTMENTS DEPT  
   3  WHERE EMP.DEPARTMENT_ID = DEPT.DEPARTMENT_ID  
   4  GROUP BY DEPT.DEPARTMENT_NAME  
   5  ORDER BY DEPT.DEPARTMENT_NAME;  
   
DEPARTMENT_NAME                AVG(EMP.SALARY)   COUNT(*)  
------------------------------ --------------- ----------  
Accounting                               10150          2  
Administration                            4400          1  
Executive                      21333.333333333          3  
Finance                                   8600          6  
Human Resources                           6500          1  
IT                                        5760          5  
Marketing                                 9500          2  
Public Relations                         10000          1  
Purchasing                                4150          6  
Sales                          8973.8529411764         34  
Shipping                       3475.5555555555         45  
   
11 rows selected  
--可以看到，这种方式，对于部门号为空的没有统计出来  
 
/*--------4、列出每个部门中有同样工资的员工的统计信息，  
  列出他们的部门号，工资，人数。---------*/  
 
SQL> SELECT EMP1.DEPARTMENT_ID,EMP1.SALARY,COUNT(*) CNT  
   2  FROM   EMPLOYEES EMP1,EMPLOYEES EMP2  
   3  WHERE  EMP1.DEPARTMENT_ID = EMP2.DEPARTMENT_ID AND 
   4          EMP1.SALARY = EMP2.SALARY  
   5          AND EMP1.EMPLOYEE_ID <> EMP2.EMPLOYEE_ID  
   6  GROUP BY EMP1.DEPARTMENT_ID,EMP1.SALARY;  
   
DEPARTMENT_ID     SALARY        CNT  
------------- ---------- ----------  
           50    2200.00          2  
           50    2400.00          2  
           50    2500.00         20  
           50    2600.00          6  
           50    2700.00          2  
           50    2800.00          6  
           50    2900.00          2  
           50    3000.00          2  
           50    3100.00          6  
           50    3200.00         12  
           50    3300.00          2  
           50    3600.00          2  
           60    4800.00          2  
           80    7000.00          2  
           80    7500.00          2  
           80    8000.00          6  
           80    9000.00          2  
           80    9500.00          6  
           80   10000.00          6  
           80   10500.00          2   
           80   11000.00          2  
           90   20000.00          2  
   
22 rows selected  
 
/*--------5、列出同部门中工资高于1000 的员工数量超过2 人的部门，  
显示部门名字、地区名称。---------*/  
 
SQL> SELECT D.DEPARTMENT_NAME,L.CITY,COUNT(*)  
   2  FROM EMPLOYEES E,DEPARTMENTS D,LOCATIONS L  
   3  WHERE E.DEPARTMENT_ID = D.DEPARTMENT_ID AND 
   4         D.LOCATION_ID   = L.LOCATION_ID    AND 
   5         E.SALARY > 1000  
   6  GROUP BY D.DEPARTMENT_NAME,L.CITY  
   7  HAVING COUNT(*) > 2;  
   
DEPARTMENT_NAME                CITY                             COUNT(*)  
------------------------------ ------------------------------ ----------  
IT                             Southlake                               5  
Sales                          Oxford                                 34  
Finance                        Seattle                                 6  
Shipping                       South San Francisco                    45  
Executive                      Seattle                                 3  
Purchasing                     Seattle                                 6  
   
6 rows selected 

#p#

/*--------6、哪些员工的工资，高于整个公司的平均工资，  
  列出员工的名字和工资（降序）。---------*/  
 
SQL> SELECT FIRST_NAME || ' ' || LAST_NAME,SALARY  
   2  FROM EMPLOYEES  
   3  WHERE SALARY > (  
   4        SELECT AVG(SALARY)  
   5        FROM EMPLOYEES  
   6        )  
   7  ORDER BY SALARY DESC;   
FIRST_NAME||''||LAST_NAME                          SALARY  
---------------------------------------------- ----------  
Steven King                                      24000.00  
Neena Kochhar                                    20000.00  
Lex De Haan                                      20000.00  
John Russell                                     14000.00  
Karen Partners                                   13500.00  
Michael Hartstein                                13000.00  
Nancy Greenberg                                  12000.00  
Alberto Errazuriz                                12000.00  
Shelley Higgins                                  12000.00  
Lisa Ozer                                        11500.00  
Den Raphaely                                     11000.00  
Gerald Cambrault                                 11000.00  
Ellen Abel                                       11000.00  
Eleni Zlotkey                                    10500.00  
Clara Vishney                                    10500.00  
Peter Tucker                                     10000.00  
Janette King                                     10000.00  
Harrison Bloom                                   10000.00  
Hermann Baer                                     10000.00  
Tayler Fox                                        9600.00  
--共50条数据  
 
/*--------7、哪些员工的工资，介于50号 和80号 部门平均工资之间。---------*/  
 
SQL> SELECT FIRST_NAME || ' ' || LAST_NAME AS NAME,SALARY  
  2  FROM EMPLOYEES  
  3  WHERE SALARY  
  4  BETWEEN 
  5      (SELECT AVG(SALARY) FROM EMPLOYEES  
  6       WHERE DEPARTMENT_ID = 50)  
  7  AND (SELECT AVG(SALARY) FROM EMPLOYEES  
  8       WHERE DEPARTMENT_ID = 80);  
   
NAME                                               SALARY  
---------------------------------------------- ----------  
Bruce Ernst                                       6000.00  
David Austin                                      4800.00  
Valli Pataballa                                   4800.00  
Diana Lorentz                                     4200.00  
John Chen                                         8200.00  
Ismael Sciarra                                    7700.00  
Jose Manuel Urman                                 7800.00  
Luis Popp                                         6900.00  
Matthew Weiss                                     8000.00  
Adam Fripp                                        8200.00  
Payam Kaufling                                    7900.00  
Shanta Vollman                                    6500.00  
Kevin Mourgos                                     5800.00  
Renske Ladwig                                     3600.00  
Trenna Rajs                                       3500.00  
Christopher Olsen                                 8000.00  
Nanette Cambrault                                 7500.00  
Oliver Tuvault                                    7000.00  
Lindsey Smith                                     8000.00  
Louise Doran                                      7500.00  
Sarath Sewall                                     7000.00  
Mattea Marvins                                    7200.00  
David Lee                                         6800.00  
Sundar Ande                                       6400.00  
Amit Banda                                        6200.00  
William Smith                                     7400.00  
Elizabeth Bates                                   7300.00  
Sundita Kumar                                     6100.00  
Alyssa Hutton                                     8800.00  
Jonathon Taylor                                   8600.00  
Jack Livingston                                   8000.00  
Kimberely Grant                                   7000.00  
Charles Johnson                                   7211.00  
Nandita Sarchand                                  4200.00  
Alexis Bull                                       4100.00  
Kelly Chung                                       3800.00  
Jennifer Dilly                                    3600.00  
Sarah Bell                                        4000.00  
Britney Everett                                   3900.00  
Jennifer Whalen                                   4400.00  
Pat Fay                                           6000.00  
Susan Mavris                                      6500.00  
William Gietz                                     8300.00  
   
43 rows selected  
 
/*--------8、所在部门平均工资高于5000 的员工名字。---------*/  
 
SQL> SELECT FIRST_NAME || ' ' || LAST_NAME AS NAME,SALARY  
   2  FROM EMPLOYEES  
   3  WHERE DEPARTMENT_ID IN 
   4        (SELECT DEPARTMENT_ID FROM EMPLOYEES  
   5         GROUP BY DEPARTMENT_ID  
   6         HAVING AVG(SALARY) > 5000);  
   
NAME                                               SALARY  
---------------------------------------------- ----------  
Michael Hartstein                                13000.00  
Pat Fay                                           6000.00  
Susan Mavris                                      6500.00  
Alexander Hunold                                  9000.00  
Bruce Ernst                                       6000.00  
David Austin                                      4800.00  
Valli Pataballa                                   4800.00  
Diana Lorentz                                     4200.00  
Hermann Baer                                     10000.00  
John Russell                                     14000.00  
Karen Partners                                   13500.00  
Alberto Errazuriz                                12000.00  
Gerald Cambrault                                 11000.00  
Eleni Zlotkey                                    10500.00  
Peter Tucker                                     10000.00  
David Bernstein                                   9500.00  
Peter Hall                                        9000.00  
Christopher Olsen                                 8000.00  
Nanette Cambrault                                 7500.00  
Oliver Tuvault                                    7000.00  
--等54行数据…  
 
/*--------9、列出各个部门中工资最高的员工的信息：名字、部门号、工资。---------*/  
 
SQL> SELECT FIRST_NAME || ' ' || LAST_NAME AS NAME 
   2         ,SALARY,DEPARTMENT_ID  
   3  FROM EMPLOYEES  
   4  WHERE (DEPARTMENT_ID,SALARY) IN 
   5        (SELECT DEPARTMENT_ID,MAX(SALARY)  
   6         FROM EMPLOYEES  
   7         GROUP BY DEPARTMENT_ID);   
 
NAME                                               SALARY DEPARTMENT_ID  
---------------------------------------------- ---------- -------------  
Jennifer Whalen                                   4400.00            10  
Michael Hartstein                                13000.00            20  
Den Raphaely                                     11000.00            30  
Susan Mavris                                      6500.00            40  
Adam Fripp                                        8200.00            50  
Alexander Hunold                                  9000.00            60  
Hermann Baer                                     10000.00            70  
John Russell                                     14000.00            80  
Steven King                                      24000.00            90  
Nancy Greenberg                                  12000.00           100  
Shelley Higgins                                  12000.00           110  
   
11 rows selected  
 
/*--------10、最高的部门平均工资是多少。---------*/  
SQL> SELECT MAX(AVGSALARY)  
  2  FROM(SELECT DEPARTMENT_ID,AVG(SALARY) AVGSALARY  
  3    FROM EMPLOYEES  
  4    GROUP BY DEPARTMENT_ID);  
   
MAX(AVGSALARY)  
--------------  
21333.33333333 

原文链接：http://www.cnblogs.com/huyong/archive/2011/06/22/2086772.html

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