MySQL经典18道sql试题
Employees MySQL经典18道sql试题
为了培养新人，本人特别准备了18道MySQL sql试题，题不在于多，而在于精，意在锻炼他们对表结构的认识，数据库函数的调用，业务的理解上。废话不说直接上题，答案暂时不公布，先让他们动动脑筋。
本套试题所涉及到的库为MySQL经典的Employees库，关联图如下：
mysql> use employees;
Database changed
mysql> select table_name,table_schema,table_rows from information_schema.tables where table_schema='employees';
+----------------+--------------+------------+
| table_name | table_schema | table_rows |
+----------------+--------------+------------+
| departments | employees | 9 |
| dept_emp | employees | 331143 |
| dept_manager | employees | 24 |
| employees | employees | 299556 |
| salaries | employees | 2838426 |
| temp_employees | employees | 10 |
| titles | employees | 442248 |
+----------------+--------------+------------+
7 rows in set (0.00 sec)
1、统计人力资源部(Human Resources)一共有多少人任职(包括在职和离职)，字段包括员工数量(count)。
输出结果如下。
+-------+
| count |
+-------+
| 17786 |
+-------+
2、统计开发部(Development)在1990年，一年里入职又离职的员工信息，字段包括员工编号(emp_no)，员工编号(名称)，入职日期(from_date)，离职日期(to_date)。
输出结果如下。
+--------+--------------+------------+------------+
| emp_no | last_name | from_date | to_date |
+--------+--------------+------------+------------+
| 10902 | Perly | 1990-06-11 | 1990-09-25 |
| 15194 | Rosar | 1990-08-21 | 1990-08-24 |
| 25495 | Lakshmanan | 1990-08-20 | 1990-10-04 |
| 32890 | Horswill | 1990-08-13 | 1990-08-14 |
| 33090 | Syrzycki | 1990-08-13 | 1990-11-08 |
| 38357 | Turnbull | 1990-09-04 | 1990-10-04 |
| 38691 | Denos | 1990-04-18 | 1990-05-04 |
| 39802 | Rodier | 1990-09-15 | 1990-11-01 |
| 42026 | Impagliazzo | 1990-01-06 | 1990-09-07 |
| 59088 | Lowrie | 1990-02-16 | 1990-03-31 |
| 65478 | Baja | 1990-06-22 | 1990-07-04 |
| 73856 | Rathonyi | 1990-05-05 | 1990-08-11 |
| 75543 | Valiente | 1990-02-08 | 1990-11-22 |
| 80993 | Kavraki | 1990-02-26 | 1990-04-11 |
| 86446 | Awdeh | 1990-04-04 | 1990-05-03 |
| 87548 | Doering | 1990-06-16 | 1990-06-20 |
| 96872 | Munke | 1990-01-06 | 1990-01-14 |
| 99437 | Thiran | 1990-01-12 | 1990-08-08 |
| 104794 | Hofman | 1990-02-20 | 1990-12-17 |
| 107127 | Madeira | 1990-03-20 | 1990-04-13 |
| 201815 | Cooke | 1990-06-27 | 1990-11-10 |
| 203700 | Seuren | 1990-07-22 | 1990-09-22 |
| 204773 | Vesna | 1990-07-07 | 1990-10-09 |
| 209747 | Millington | 1990-04-08 | 1990-12-22 |
| 212020 | Liedekerke | 1990-04-11 | 1990-08-23 |
| 212119 | Randi | 1990-01-30 | 1990-08-23 |
| 217590 | Lamba | 1990-05-21 | 1990-12-16 |
| 219460 | Shimshoni | 1990-01-11 | 1990-11-25 |
| 222006 | Gimbel | 1990-10-13 | 1990-10-13 |
| 233261 | Lally | 1990-02-01 | 1990-06-01 |
| 236998 | Cummings | 1990-04-28 | 1990-08-19 |
| 238135 | Heijenga | 1990-04-07 | 1990-11-02 |
| 239469 | Merli | 1990-01-24 | 1990-08-16 |
| 241112 | Bharadwaj | 1990-06-10 | 1990-07-17 |
| 245024 | Zhiwei | 1990-05-18 | 1990-09-17 |
| 247263 | Schach | 1990-03-24 | 1990-12-07 |
| 247661 | Sabnani | 1990-04-19 | 1990-07-05 |
| 253013 | Brandsma | 1990-07-07 | 1990-11-24 |
| 256418 | Ulupinar | 1990-06-23 | 1990-07-15 |
| 257472 | Pashtan | 1990-08-16 | 1990-12-22 |
| 259776 | Baez | 1990-01-04 | 1990-12-20 |
| 260699 | Staudhammer | 1990-06-09 | 1990-08-02 |
| 261227 | Munke | 1990-07-14 | 1990-09-17 |
| 262481 | Swiss | 1990-04-22 | 1990-11-19 |
| 271302 | Herath | 1990-01-05 | 1990-05-22 |
| 275235 | Covnot | 1990-09-01 | 1990-09-25 |
| 276038 | Bellmore | 1990-08-03 | 1990-12-05 |
| 276253 | Luef | 1990-07-09 | 1990-12-22 |
| 277339 | Kamble | 1990-08-28 | 1990-10-23 |
| 279822 | Kalsbeek | 1990-03-05 | 1990-04-13 |
| 285432 | Karcich | 1990-07-31 | 1990-08-16 |
| 285586 | Silva | 1990-09-01 | 1990-11-22 |
| 288724 | Ouhyoung | 1990-01-16 | 1990-10-24 |
| 289271 | Macedo | 1990-01-27 | 1990-03-05 |
| 295205 | Schwabacher | 1990-01-03 | 1990-06-07 |
| 296608 | Ravishankar | 1990-07-05 | 1990-07-12 |
| 400181 | Gurbaxani | 1990-01-22 | 1990-04-11 |
| 401024 | Rotem | 1990-06-15 | 1990-11-20 |
| 402369 | Emmart | 1990-08-17 | 1990-12-14 |
| 404442 | Bahk | 1990-10-26 | 1990-12-03 |
| 412045 | Bolotov | 1990-07-29 | 1990-08-07 |
| 416310 | Schapire | 1990-03-16 | 1990-12-29 |
| 418567 | Nollmann | 1990-08-19 | 1990-09-16 |
| 421381 | Heusch | 1990-08-20 | 1990-09-03 |
| 424000 | Zlotek | 1990-08-30 | 1990-11-06 |
| 424227 | Birke | 1990-04-21 | 1990-12-25 |
| 432473 | Plesums | 1990-02-03 | 1990-08-20 |
| 436610 | Garnham | 1990-04-16 | 1990-11-28 |
| 441212 | Picaronny | 1990-05-27 | 1990-09-18 |
| 441423 | Irland | 1990-01-15 | 1990-05-20 |
| 442169 | Vidya | 1990-11-09 | 1990-11-24 |
| 444955 | Provine | 1990-06-07 | 1990-09-23 |
| 447339 | Demos | 1990-10-31 | 1990-11-17 |
| 451512 | Roisin | 1990-11-05 | 1990-11-29 |
| 456501 | Bierman | 1990-04-12 | 1990-07-19 |
| 457109 | Baaz | 1990-04-27 | 1990-06-12 |
| 465347 | Peroz | 1990-02-10 | 1990-06-01 |
| 465879 | Mullainathan | 1990-06-23 | 1990-12-29 |
| 470097 | Constantine | 1990-06-03 | 1990-10-19 |
| 470701 | Cyre | 1990-08-15 | 1990-11-26 |
| 480924 | Busillo | 1990-02-26 | 1990-03-03 |
| 481369 | Coombs | 1990-03-21 | 1990-09-21 |
| 483274 | Lichtner | 1990-01-25 | 1990-11-28 |
| 487291 | Thorensen | 1990-09-20 | 1990-11-12 |
| 489277 | Yamaashi | 1990-11-17 | 1990-12-28 |
| 490851 | Plotkin | 1990-04-11 | 1990-05-27 |
| 492491 | Peron | 1990-04-27 | 1990-08-29 |
| 496147 | Neiman | 1990-04-17 | 1990-04-17 |
+--------+--------------+------------+------------+
3、统计开发部(Development)在2000年度里，每月员工人事调动或离职的情况，并按照月份排序，字段包括月份名称(month)，员工数量(count)。
输出结果如下。
+-----------+-------+
| month | count |
+-----------+-------+
| January | 236 |
| February | 251 |
| March | 258 |
| April | 255 |
| May | 260 |
| June | 220 |
| July | 243 |
| August | 246 |
| September | 247 |
| October | 230 |
| November | 233 |
| December | 227 |
+-----------+-------+
4、统计开发部(Development)在2000年1月份，每天员工离职的情况，并按照日期排序，字段包括日期(day)，员工数量(count)。
输出结果如下。
+------+-------+
| day | count |
+------+-------+
| 1 | 6 |
| 2 | 10 |
| 3 | 6 |
| 4 | 3 |
| 5 | 10 |
| 6 | 8 |
| 7 | 6 |
| 8 | 6 |
| 9 | 11 |
| 10 | 5 |
| 11 | 6 |
| 12 | 7 |
| 13 | 3 |
| 14 | 7 |
| 15 | 7 |
| 16 | 10 |
| 17 | 7 |
| 18 | 4 |
| 19 | 13 |
| 20 | 6 |
| 21 | 14 |
| 22 | 10 |
| 23 | 6 |
| 24 | 7 |
| 25 | 5 |
| 26 | 11 |
| 27 | 13 |
| 28 | 7 |
| 29 | 9 |
| 30 | 8 |
| 31 | 5 |
+------+-------+
5、统计开发部(Development)在2000年1月份，每天员工离职的情况，并按照日期排序，字段包括日期(day)，星星数量(stars)。
输出结果如下。
+------+----------------+
| day | starts |
+------+----------------+
| 1 | ****** |
| 2 | ********** |
| 3 | ****** |
| 4 | *** |
| 5 | ********** |
| 6 | ******** |
| 7 | ****** |
| 8 | ****** |
| 9 | *********** |
| 10 | ***** |
| 11 | ****** |
| 12 | ******* |
| 13 | *** |
| 14 | ******* |
| 15 | ******* |
| 16 | ********** |
| 17 | ******* |
| 18 | **** |
| 19 | ************* |
| 20 | ****** |
| 21 | ************** |
| 22 | ********** |
| 23 | ****** |
| 24 | ******* |
| 25 | ***** |
| 26 | *********** |
| 27 | ************* |
| 28 | ******* |
| 29 | ********* |
| 30 | ******** |
| 31 | ***** |
+------+----------------+
6、统计开发部(Development)在2000年1月份，不是工作日(周一到周五)员工离职的情况，并按照周一到周五排序，字段包括日期(dayname)，星星数量(count)。
输出结果如下。
+-----------+-------+
| dayname | count |
+-----------+-------+
| Monday | 30 |
| Tuesday | 18 |
| Wednesday | 41 |
| Thursday | 30 |
| Friday | 34 |
+-----------+-------+
7、对各部门的在职员工数进行排序，希望有如下所示的结果集，字段包括名次(rank),员工数量(count)。
+--------------------+-------+
| dept_name | count |
+--------------------+-------+
| Development | 61386 |
| Production | 53304 |
| Sales | 37701 |
| Customer Service | 17569 |
| Research | 15441 |
| Marketing | 14842 |
| Quality Management | 14546 |
| Human Resources | 12898 |
| Finance | 12437 |
+--------------------+-------+
输出结果如下。
+------+-------+
| rank | count |
+------+-------+
| 1 | 61386 |
| 2 | 53304 |
| 3 | 37701 |
| 4 | 17569 |
| 5 | 15441 |
| 6 | 14842 |
| 7 | 14546 |
| 8 | 12898 |
| 9 | 12437 |
+------+-------+
8、对各部门的在职员工数进行横向排序，希望有如下所示的结果集，字段包括名次(rank1-rank9)。
+------+-------+
| rank | count |
+------+-------+
| 1 | 61386 |
| 2 | 53304 |
| 3 | 37701 |
| 4 | 17569 |
| 5 | 15441 |
| 6 | 14842 |
| 7 | 14546 |
| 8 | 12898 |
| 9 | 12437 |
+------+-------+
输出结果如下。
+-------+-------+-------+-------+-------+-------+-------+-------+-------+
| rank1 | rank2 | rank3 | rank4 | rank5 | rank6 | rank7 | rank8 | rank9 |
+-------+-------+-------+-------+-------+-------+-------+-------+-------+
| 61386 | 53304 | 37701 | 17569 | 15441 | 14842 | 14546 | 12898 | 12437 |
+-------+-------+-------+-------+-------+-------+-------+-------+-------+
9、返回薪水在150000以上的在职(to_date=‘9999-01-01’)员工信息，字段包括员工编号(emp_no)，员工全名(name)，性别(gender)，生日(birth_date)，入职日期(hire_date)。
输出结果如下。
+--------+-------------------+--------+------------+------------+
| emp_no | name | gender | birth_date | hire_date |
+--------+-------------------+--------+------------+------------+
| 43624 | Tokuyasu Pesch | M | 1953-11-14 | 1985-03-26 |
| 46439 | Ibibia Junet | M | 1953-01-31 | 1985-05-20 |
| 47978 | Xiahua Whitcomb | M | 1956-03-24 | 1985-07-18 |
| 66793 | Lansing Kambil | M | 1964-05-15 | 1985-06-20 |
| 80823 | Willard Baca | M | 1963-01-21 | 1985-02-26 |
| 109334 | Tsutomu Alameldin | M | 1955-08-02 | 1985-02-15 |
| 205000 | Charmane Griswold | M | 1956-01-14 | 1990-06-23 |
| 237542 | Weicheng Hatcliff | F | 1954-10-05 | 1985-04-12 |
| 238117 | Mitsuyuki Stanfel | M | 1959-06-21 | 1988-01-03 |
| 253939 | Sanjai Luders | M | 1957-12-03 | 1987-04-15 |
| 254466 | Honesty Mukaidono | M | 1963-05-27 | 1986-08-08 |
| 266526 | Weijing Chenoweth | F | 1957-02-14 | 1986-10-08 |
| 276633 | Shin Birdsall | M | 1954-01-27 | 1987-10-08 |
| 279776 | Mohammed Moehrke | M | 1955-05-06 | 1986-06-10 |
| 493158 | Lidong Meriste | M | 1961-05-20 | 1987-05-09 |
+--------+-------------------+--------+------------+------------+
10、查找各个部门当前(to_date=‘9999-01-01’)领导当前薪水详情，字段包括部门编号(dept_no)，员工编号(emp_no)，员工名称(last_name)，薪水(salary）。
输出结果如下。
+---------+--------+------------+--------+
| dept_no | emp_no | last_name | salary |
+---------+--------+------------+--------+
| d001 | 110039 | Minakawa | 106491 |
| d002 | 110114 | Legleitner | 83457 |
| d003 | 110228 | Sigstam | 65400 |
| d004 | 110420 | Ghazalie | 56654 |
| d005 | 110567 | DasSarma | 74510 |
| d006 | 110854 | Pesch | 72876 |
| d007 | 111133 | Zhang | 101987 |
| d008 | 111534 | Kambil | 79393 |
| d009 | 111939 | Weedman | 58745 |
+---------+--------+------------+--------+
11、返回员工入职年龄在25(包含25)岁以下的1990年以后入职的在职员工信息，字段包括员工编号(emp_no)，员工名称(last_name)，员工生日(birth_date)，员工入职日期(hire_date)。
输出结果如下。
+--------+-----------+------------+------------+
| emp_no | last_name | birth_date | hire_date |
+--------+-----------+------------+------------+
| 60875 | Masaki | 1965-01-21 | 1990-01-14 |
| 74200 | Weiland | 1965-01-16 | 1990-01-02 |
| 79171 | Ellozy | 1965-01-19 | 1990-01-14 |
| 82098 | Wilharm | 1965-01-25 | 1990-01-18 |
| 218100 | Garnham | 1965-01-24 | 1990-01-02 |
| 295278 | Barvinok | 1965-01-04 | 1990-01-02 |
+--------+-----------+------------+------------+
12、返回first_name,last_name首尾字母都相同的在职员工 ，字段包括员工全名name。
输出结果如下。
+--------------------------+
| name |
+--------------------------+
| Kirk Kalsbeek |
| Hinrich Herath |
| Georg Guting |
| Snehasis Swiss |
| Snehasis Servieres |
| Eldridge Eldridge |
| Szabolcs Salinas |
| Snehasis Smeets |
| Nidapan Nicolson |
| Aria Ariola |
| Stabislas Stassinopoulos |
| Szabolcs Salinas |
| Alenka Aloia |
| Almudena Aloia |
| Eldridge Erde |
| Abdulla Akiyama |
| Rutger Ratnakar |
| Neven Naudin |
| Snehasis Swiss |
| Ebbe Etalle |
| Sreenivas Slaats |
| Arra Akiyama |
| Snehasis Stiles |
| Surveyors Staylopatis |
| Guoxiang Guting |
| Sreenivas Sullins |
| Nitsan Nollmann |
| Nitsan Naudin |
| Elrique Erbe |
| Snehasis Sifakis |
| Nakhoon Nilsson |
| Surveyors Salinas |
| Stabislas Stranks |
| Hugh Harbusch |
| Ravishankar Ravishankar |
| Alenka Azuma |
| Sreenivas Sullins |
| Kirk Koblick |
| Snehasis Swiss |
| Sreenivas Stranks |
| Navin Neiman |
+--------------------------+
13、返回头衔为Engineer的1990年以后入职薪水在40000(包括40000)元以下的在职员工 ，字段包括员工编号(emp_no)，员工名称(last_name)，员工头衔(title)。
输出结果如下。
+--------+----------------+--------------------+
| emp_no | last_name | title |
+--------+----------------+--------------------+
| 23987 | Gladwell | Engineer |
| 34145 | Rothe | Assistant Engineer |
| 39498 | Borstler | Engineer |
| 44230 | Angel | Engineer |
| 45931 | Swick | Senior Engineer |
| 47097 | Ambroszkiewicz | Engineer |
| 63966 | Kolinko | Senior Engineer |
| 65936 | Barbanera | Senior Engineer |
| 67332 | Honglei | Engineer |
| 73372 | Miculan | Engineer |
| 80271 | Zobel | Engineer |
| 85682 | Turnbull | Senior Engineer |
| 98626 | Emmerich | Engineer |
| 105604 | Esposito | Engineer |
| 108687 | Rassart | Engineer |
| 108824 | Pileggi | Engineer |
| 109200 | Budinsky | Engineer |
| 201690 | Valtorta | Engineer |
| 201768 | Muhling | Assistant Engineer |
| 209653 | Kohling | Engineer |
| 212818 | Greenaway | Engineer |
| 228121 | Reutenauer | Engineer |
| 230890 | Schmiedel | Engineer |
| 240474 | Malabarba | Engineer |
| 244413 | Jeansoulin | Engineer |
| 247851 | Vidya | Assistant Engineer |
| 250114 | Wendorf | Engineer |
| 250516 | Baig | Engineer |
| 251123 | Argence | Senior Engineer |
| 276851 | McFarlin | Engineer |
| 291280 | Yoshimura | Engineer |
| 292755 | Perelgut | Engineer |
| 293851 | Callaway | Assistant Engineer |
| 297603 | Baak | Assistant Engineer |
| 401786 | Nicolson | Engineer |
| 408129 | Engelmann | Engineer |
| 408667 | Hiroyama | Engineer |
| 420978 | Wolniewicz | Senior Engineer |
| 433565 | Kranzdorf | Senior Engineer |
| 444557 | Tsukuda | Senior Engineer |
| 456636 | Pettey | Engineer |
| 459496 | Gaughan | Senior Engineer |
| 463145 | Zweizig | Senior Engineer |
| 463548 | Huhdanpaa | Engineer |
| 464323 | Curless | Engineer |
| 466226 | Talmor | Engineer |
| 467021 | Kruskal | Engineer |
| 473398 | Ouhyoung | Engineer |
| 474751 | Stassinopoulos | Engineer |
| 475590 | Jiafu | Engineer |
| 479802 | Kalsbeek | Engineer |
| 499891 | Weedman | Senior Engineer |
+--------+----------------+--------------------+
14、返回人力资源部(Human Resources)最年轻的男(M)性在职员工，字段包括部门名称员工编号(emp_no)，员工名称(last_name)，部门名称(dept_name)，性别(gender)，生日(birth_date)。
输出结果如下。
+--------+-----------+-----------------+--------+------------+
| emp_no | last_name | dept_name | gender | birth_date |
+--------+-----------+-----------------+--------+------------+
| 65308 | Pocchiola | Human Resources | M | 1952-02-01 |
+--------+-----------+-----------------+--------+------------+
15、将员工分成若干个组，一个组最多8人，结果显示如下，字段包括组号(grp)，员工编号(emp_no)，员工名称(last_name)。
注意：解答此题前先执行以下语句：
DROP TABLE if exists employees.temp_employees ;
CREATE TABLE if not exists employees.temp_employees AS SELECT e.emp_no, e.last_name FROM
employees e
ORDER BY e.emp_no
LIMIT 32;
表：temp_employees
+--------+-------------+
| emp_no | last_name |
+--------+-------------+
| 10001 | Facello |
| 10002 | Simmel |
| 10003 | Bamford |
| 10004 | Koblick |
| 10005 | Maliniak |
| 10006 | Preusig |
| 10007 | Zielinski |
| 10008 | Kalloufi |
| 10009 | Peac |
| 10010 | Piveteau |
| 10011 | Sluis |
| 10012 | Bridgland |
| 10013 | Terkki |
| 10014 | Genin |
| 10015 | Nooteboom |
| 10016 | Cappelletti |
| 10017 | Bouloucos |
| 10018 | Peha |
| 10019 | Haddadi |
| 10020 | Warwick |
| 10021 | Erde |
| 10022 | Famili |
| 10023 | Montemayor |
| 10024 | Pettey |
| 10025 | Heyers |
| 10026 | Berztiss |
| 10027 | Reistad |
| 10028 | Tempesti |
| 10029 | Herbst |
| 10030 | Demeyer |
| 10031 | Joslin |
| 10032 | Reistad |
+--------+-------------+
输出结果如下。
+------+--------+-------------+
| grp | emp_no | last_name |
+------+--------+-------------+
| 1 | 10028 | Tempesti |
| 1 | 10032 | Reistad |
| 1 | 10025 | Heyers |
| 1 | 10029 | Herbst |
| 1 | 10026 | Berztiss |
| 1 | 10030 | Demeyer |
| 1 | 10027 | Reistad |
| 1 | 10031 | Joslin |
| 2 | 10020 | Warwick |
| 2 | 10024 | Pettey |
| 2 | 10017 | Bouloucos |
| 2 | 10021 | Erde |
| 2 | 10018 | Peha |
| 2 | 10022 | Famili |
| 2 | 10019 | Haddadi |
| 2 | 10023 | Montemayor |
| 3 | 10012 | Bridgland |
| 3 | 10016 | Cappelletti |
| 3 | 10009 | Peac |
| 3 | 10013 | Terkki |
| 3 | 10010 | Piveteau |
| 3 | 10014 | Genin |
| 3 | 10011 | Sluis |
| 3 | 10015 | Nooteboom |
| 4 | 10004 | Koblick |
| 4 | 10008 | Kalloufi |
| 4 | 10001 | Facello |
| 4 | 10005 | Maliniak |
| 4 | 10002 | Simmel |
| 4 | 10006 | Preusig |
| 4 | 10003 | Bamford |
| 4 | 10007 | Zielinski |
+------+--------+-------------+
16、请以当前日期为基准(2020-07-04)分别求出员工编号为10134,10200,10425,10434,10449,10459,10466,10532的任职情况,字段包括员工编号(emp_no)，入职日期(from_date)，离职日期(to_date)，工作年限(years)，状态(status)。
输出结果如下。
+--------+---------+------------+------------+-------+--------+
| emp_no | dept_no | from_date | to_date | years | status |
+--------+---------+------------+------------+-------+--------+
| 10134 | d004 | 1993-12-02 | 9999-01-01 | 26 | on |
| 10134 | d005 | 1987-12-12 | 1993-12-02 | 5 | off |
| 10425 | d004 | 1995-05-07 | 2002-05-06 | 6 | off |
| 10434 | d004 | 1995-06-27 | 2002-06-22 | 6 | off |
| 10449 | d001 | 1996-03-12 | 9999-01-01 | 24 | on |
| 10449 | d007 | 1987-03-28 | 1996-03-12 | 8 | off |
| 10459 | d002 | 1998-06-14 | 9999-01-01 | 22 | on |
| 10459 | d003 | 1997-06-28 | 1998-06-14 | 0 | off |
| 10466 | d009 | 1997-08-22 | 2000-08-15 | 2 | off |
+--------+---------+------------+------------+-------+--------+
17、公司规定，新员工必须要进行1次岗前培训，培训是1个月2次，分别为每个月的第1个星期五和最后1个星期五，
请给以下员工编号为10019,10298,10684,11325,11697,11754,11829,12015,12299,12389,15368,16166的员工安排培训日期，字段包括员工编号(emp_no)，入职日期(from_date)，培训日期(edu_date)。
希望得到以下结果，你安排对了吗？
输出结果如下。
+--------+------------+------------+
| emp_no | hire_date | edu_date |
+--------+------------+------------+
| 10019 | 1999-04-30 | 1999-04-30 |
| 10298 | 1999-03-30 | 1999-04-02 |
| 10684 | 1999-10-28 | 1999-10-29 |
| 11325 | 1999-01-10 | 1999-01-29 |
| 11697 | 1999-11-06 | 1999-11-26 |
| 11754 | 1999-08-23 | 1999-08-27 |
| 11829 | 1999-02-17 | 1999-02-26 |
| 12015 | 1999-01-04 | 1999-01-29 |
| 12299 | 1999-01-24 | 1999-01-29 |
| 12389 | 1999-10-08 | 1999-10-29 |
| 15368 | 1999-04-01 | 1999-04-02 |
| 16166 | 1999-03-04 | 1999-03-05 |
+--------+------------+------------+
18、请对以下离职员(10008,10011,10021,10025,10028)工薪资变动情况做一下统计，希望得到如下结果，字段包括员工编号(emp_no)，开始日期(from_date)，结束日期(to_date)。
+--------+--------+------------+------------+
| emp_no | salary | from_date | to_date |
+--------+--------+------------+------------+
| 10008 | 46671 | 1998-03-11 | 1999-03-11 |
| 10008 | 48584 | 1999-03-11 | 2000-03-10 |
| 10008 | 52668 | 2000-03-10 | 2000-07-31 |
| 10011 | 42365 | 1990-01-22 | 1991-01-22 |
| 10011 | 44200 | 1991-01-22 | 1992-01-22 |
| 10011 | 48214 | 1992-01-22 | 1993-01-21 |
| 10011 | 50927 | 1993-01-21 | 1994-01-21 |
| 10011 | 51470 | 1994-01-21 | 1995-01-21 |
| 10011 | 54545 | 1995-01-21 | 1996-01-21 |
| 10011 | 56753 | 1996-01-21 | 1996-11-09 |
| 10021 | 55025 | 1988-02-10 | 1989-02-09 |
| 10021 | 56399 | 1989-02-09 | 1990-02-09 |
| 10021 | 59700 | 1990-02-09 | 1991-02-09 |
| 10021 | 60851 | 1991-02-09 | 1992-02-09 |
| 10021 | 61117 | 1992-02-09 | 1993-02-08 |
| 10021 | 60708 | 1993-02-08 | 1994-02-08 |
| 10021 | 63514 | 1994-02-08 | 1995-02-08 |
| 10021 | 66249 | 1995-02-08 | 1996-02-08 |
| 10021 | 70570 | 1996-02-08 | 1997-02-07 |
| 10021 | 74759 | 1997-02-07 | 1998-02-07 |
| 10021 | 77519 | 1998-02-07 | 1999-02-07 |
| 10021 | 77237 | 1999-02-07 | 2000-02-07 |
| 10021 | 79631 | 2000-02-07 | 2001-02-06 |
| 10021 | 82295 | 2001-02-06 | 2002-02-06 |
| 10021 | 84169 | 2002-02-06 | 2002-07-15 |
| 10025 | 40000 | 1987-08-17 | 1988-08-16 |
| 10025 | 44416 | 1988-08-16 | 1989-08-16 |
| 10025 | 48680 | 1989-08-16 | 1990-08-16 |
| 10025 | 50120 | 1990-08-16 | 1991-08-16 |
| 10025 | 50980 | 1991-08-16 | 1992-08-15 |
| 10025 | 54459 | 1992-08-15 | 1993-08-15 |
| 10025 | 54395 | 1993-08-15 | 1994-08-15 |
| 10025 | 56643 | 1994-08-15 | 1995-08-15 |
| 10025 | 57585 | 1995-08-15 | 1996-08-14 |
| 10025 | 57110 | 1996-08-14 | 1997-08-14 |
| 10025 | 57157 | 1997-08-14 | 1997-10-15 |
| 10028 | 48859 | 1991-10-22 | 1992-10-21 |
| 10028 | 50805 | 1992-10-21 | 1993-10-21 |
| 10028 | 52082 | 1993-10-21 | 1994-10-21 |
| 10028 | 54949 | 1994-10-21 | 1995-10-21 |
| 10028 | 55963 | 1995-10-21 | 1996-10-20 |
| 10028 | 57831 | 1996-10-20 | 1997-10-20 |
| 10028 | 58502 | 1997-10-20 | 1998-04-06 |
+--------+--------+------------+------------+
输出结果如下。
+--------+------------+------------+
| emp_no | from_date | to_date |
+--------+------------+------------+
| 10008 | 1998-03-11 | 2000-07-31 |
| 10011 | 1990-01-22 | 1996-11-09 |
| 10021 | 1988-02-10 | 2002-07-15 |
| 10025 | 1987-08-17 | 1997-10-15 |
| 10028 | 1991-10-22 | 1998-04-06 |
+--------+------------+------------+