1 --1、查询所有的课程的名称以及对应的任课老师姓名

2 SELECT

3 c.cname,4 t.tname5 FROM

6 course c7 LEFT JOIN teacher t ON c.teacher_id =t.tid;8

9 --2、查询学生表中男女生各有多少人

10 SELECT

11 gender,12 count(sid)count

13 FROM

14 student15 GROUP BY

16 gender;17

18 --3、查询物理成绩等于100的学生的姓名

19 SELECT

20 a.sid,21 b.sname22 FROM

23 score a24 LEFT JOIN student b ON a.student_id =b.sid25 WHERE

26 a.num = 100

27 AND a.course_id =(28 SELECT

29 c.cid30 FROM

31 course c32 WHERE

33 c.cname ="物理"34 );35

36 --4、查询平均成绩大于八十分的同学的姓名和平均成绩

37 SELECT

38 a.sname,39 c.avg_score40 FROM

41 student a42 INNER JOIN(43 SELECT

44 b.*, AVG(b.num)avg_score45 FROM

46 score b47 GROUP BY

48 b.student_id49 HAVING

50 avg_score > 80

51 )c ON a.sid =c.student_id;52

53 --5、查询所有学生的学号，姓名，选课数，总成绩

54 SELECT

55 a.sid,56 a.sname,57 c.count_course,58 c.sum_score59 FROM

60 student a61 LEFT JOIN(62 SELECT

63 b.student_id,64 count(b.course_id)count_course,65 SUM(b.num)sum_score66 FROM

67 score b68 GROUP BY

69 b.student_id70 )c ON a.sid =c.student_id;71

72 --6、 查询姓李老师的个数

73 SELECT

74 count(tid)75 FROM

76 teacher t77 WHERE

78 t.tname LIKE "李%";79

80 --7、 查询没有报李平老师课的学生姓名

81 SELECT

82 a.sname83 FROM

84 student a85 WHERE

86 a.sid NOT IN(87 SELECT

88 b.student_id89 FROM

90 score b91 WHERE

92 course_id IN(93 SELECT

94 c.cid95 FROM

96 course c97 WHERE

98 c.teacher_id IN(99 SELECT

100 d.tid101 FROM

102 teacher d103 WHERE

104 d.tname ="李平老师"105 )106 )107 );108

109 --8、 查询物理课程比生物课程高的学生的学号

110 SELECT

111 c.student_id112 FROM

113 (114 SELECT

115 *

116 FROM

117 score a118 WHERE

119 a.course_id =(120 SELECT

121 b.cid122 FROM

123 course b124 WHERE

125 b.cname ="物理"126 )127 )c128 INNER JOIN(129 SELECT

130 *

131 FROM

132 score d133 WHERE

134 d.course_id =(135 SELECT

136 f.cid137 FROM

138 course f139 WHERE

140 f.cname ="生物"141 )142 )g ON c.student_id =g.student_id143 AND c.num >g.num;144

145 --9、 查询没有同时选修物理课程和体育课程的学生姓名

146 SELECT

147 a.sname148 FROM

149 student a150 WHERE

151 a.sid NOT IN(152 SELECT

153 d.student_id154 FROM

155 (156 SELECT

157 *

158 FROM

159 score b160 WHERE

161 b.course_id =(162 SELECT

163 c.cid164 FROM

165 course c166 WHERE

167 c.cname ="物理"168 )169 )d170 INNER JOIN(171 SELECT

172 *

173 FROM

174 score f175 WHERE

176 f.course_id =(177 SELECT

178 g.cid179 FROM

180 course g181 WHERE

182 g.cname ="体育"183 )184 )h ON d.student_id =h.student_id185 );186

187 --10、查询挂科超过两门(包括两门)的学生姓名和班级

188 SELECT

189 c.sname,190 c.caption191 FROM

192 (193 SELECT

194 *

195 FROM

196 student a197 LEFT JOIN class b ON a.class_id =b.cid198 )c199 INNER JOIN(200 SELECT

201 d.student_id,202 count(d.student_id)count

203 FROM

204 score d205 WHERE

206 d.num < 60

207 GROUP BY

208 d.student_id209 HAVING

210 count >= 2

211 )e ON c.sid =e.student_id;212

213 --11、查询选修了所有课程的学生姓名

214 SELECT

215 s.sname216 FROM

217 student s218 INNER JOIN(219 SELECT

220 a.student_id,221 count(a.course_id)count_course222 FROM

223 score a224 GROUP BY

225 a.student_id226 HAVING

227 count_course =(SELECT count(*) FROMcourse)228 )b ON s.sid =b.student_id;229

230 --12、查询李平老师教的课程的所有成绩记录

231 SELECT

232 a.*

233 FROM

234 score a235 WHERE

236 a.course_id IN(237 SELECT

238 b.cid239 FROM

240 course b241 WHERE

242 b.teacher_id =(243 SELECT

244 c.tid245 FROM

246 teacher c247 WHERE

248 c.tname ="李平老师"249 )250 )251

252 --13、查询全部学生都选修了的课程号和课程名

253 SELECT

254 c.cid,255 c.cname256 FROM

257 course c258 INNER JOIN(259 SELECT

260 a.course_id,261 count(a.student_id)count_student262 FROM

263 score a264 GROUP BY

265 a.course_id266 HAVING

267 count_student =(SELECT count(*) FROMstudent)268 )b ON c.cid =b.course_id;269

270 --14、查询每门课程被选修的次数

271 SELECT

272 c.cid,273 c.cname,274 b.count_student275 FROM

276 course c277 LEFT JOIN(278 SELECT

279 a.course_id,280 count(a.student_id)count_student281 FROM

282 score a283 GROUP BY

284 a.course_id285 )b ON c.cid =b.course_id;286

287 --15、查询只选修了一门课程的学生姓名和学号

288 SELECT

289 s.sname290 FROM

291 student s292 INNER JOIN(293 SELECT

294 a.student_id,295 count(a.course_id)count_course296 FROM

297 score a298 GROUP BY

299 a.student_id300 HAVING

301 count_course = 1

302 )b ON s.sid =b.student_id;303

304 --16、查询所有学生考出的成绩并按从高到低排序(成绩去重)

305 SELECT DISTINCT

306 (num)307 FROM

308 score a309 ORDER BY

310 a.num DESC

311

312 --17、查询平均成绩大于85的学生姓名和平均成绩

313 SELECT

314 a.sname315 FROM

316 student a317 INNER JOIN(318 SELECT

319 b.student_id,320 avg(b.num)avg_num321 FROM

322 score b323 GROUP BY

324 b.student_id325 HAVING

326 avg_num > 85

327 )c ON a.sid =c.student_id;328

329 --18、查询生物成绩不及格的学生姓名和对应生物分数

330 SELECT

331 a.sname,332 c.num333 FROM

334 student a335 INNER JOIN(336 SELECT

337 b.student_id,338 b.num339 FROM

340 score b341 WHERE

342 b.course_id =(343 SELECT

344 cid345 FROM

346 course347 WHERE

348 cname ="生物"349 )350 AND b.num < 60

351 )c ON a.sid =c.student_id;352

353 --19、查询在所有选修了李平老师课程的学生中，这些课程(李平老师的课程，不是所有课程)平均成绩最高的学生姓名

354 SELECT

355 sname356 FROM

357 student358 WHERE

359 sid =(360 SELECT

361 a.student_id362 FROM

363 score a364 WHERE

365 a.course_id IN(366 SELECT

367 b.cid368 FROM

369 course b370 WHERE

371 b.teacher_id =(372 SELECT

373 c.tid374 FROM

375 teacher c376 WHERE

377 c.tname ="李平老师"378 )379 )380 GROUP BY

381 a.student_id382 ORDER BY

383 avg(num)DESC

384 LIMIT 1

385 )386

387 --20、查询每门课程成绩最好的前两名学生姓名

388 SELECT

389 e.sname,390 f.course_id,391 f.num392 FROM

393 student e394 INNER JOIN(395 SELECT

396 c.*

397 FROM

398 score c399 INNER JOIN(400 SELECT

401 *

402 FROM

403 (404 SELECT

405 course_id,406 MAX(num)num407 FROM

408 score409 GROUP BY

410 course_id411 ORDER BY

412 course_id,413 num DESC

414 )a415 UNION ALL

416 (417 SELECT

418 a.course_id,419 MAX(a.num)num420 FROM

421 score a422 INNER JOIN(423 SELECT

424 course_id,425 MAX(num)num426 FROM

427 score428 GROUP BY

429 course_id430 ORDER BY

431 course_id,432 num DESC

433 )b ON a.course_id =b.course_id434 WHERE

435 a.num

437 a.course_id438 )439 )d ON c.course_id =d.course_id440 WHERE

441 c.num =d.num442 ORDER BY

443 c.course_id,444 c.num DESC

445 )f ON e.sid =f.student_id446 ORDER BY

447 f.course_id,448 f.num DESC

449

450 --21、查询不同课程但成绩相同的学号，课程号，成绩

451 SELECT

452 student_id,453 course_id,454 num455 FROM

456 score457 WHERE

458 num IN(459 SELECT

460 a.num461 FROM

462 (463 SELECT

464 *

465 FROM

466 score467 GROUP BY

468 course_id,469 num470 )a471 GROUP BY

472 a.num473 HAVING

474 count(a.num)> 1

475 )476 ORDER BY

477 num;478

479 --22、查询没学过“叶平”老师课程的学生姓名以及选修的课程名称；

480 SELECT

481 c.sname,482 GROUP_CONCAT(d.cname)483 FROM

484 (485 SELECT

486 a.*, b.course_id487 FROM

488 (489 SELECT

490 *

491 FROM

492 student493 WHERE

494 sid NOT IN(495 SELECT DISTINCT

496 (student_id)497 FROM

498 score499 WHERE

500 course_id IN(501 SELECT

502 cid503 FROM

504 course505 WHERE

506 teacher_id =(507 SELECT

508 tid509 FROM

510 teacher511 WHERE

512 tname ="李平老师"513 )514 )515 )516 )a517 INNER JOIN score b ON a.sid =b.student_id518 )c519 INNER JOIN course d ON c.course_id =d.cid520 GROUP BY

521 c.sname522

523 --23、查询所有选修了学号为1的同学选修过的一门或者多门课程的同学学号和姓名；

524 SELECT

525 a.sid,526 a.sname527 FROM

528 student a529 INNER JOIN(530 SELECT

531 student_id532 FROM

533 score534 WHERE

535 student_id != 1

536 AND course_id IN(537 SELECT

538 course_id539 FROM

540 score541 WHERE

542 student_id = 1

543 )544 GROUP BY

545 student_id546 )b ON a.sid =b.student_id547

548 --24、任课最多的老师中学生单科成绩最高的学生姓名

549 SELECT

550 sname551 FROM

552 student553 WHERE

554 sid =(555 SELECT

556 student_id557 FROM

558 score559 WHERE

560 course_id IN(561 SELECT

562 cid563 FROM

564 course565 WHERE

566 teacher_id =(567 SELECT

568 teacher_id569 FROM

570 course571 GROUP BY

572 teacher_id573 ORDER BY

574 count(teacher_id)DESC

575 LIMIT 1

576 )577 )578 ORDER BY

579 num DESC

580 LIMIT 1

581 )