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 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435
| -- 1、查询"01"课程比"02"课程成绩高的学生的信息及课程分数 # 内联查询学生, 然后查询学生成绩 ,最后比较两个学生的成绩 SELECT s.s_id,s.s_name,s1.s_score AS '01_score', s2.s_score AS '02_score' FROM student s INNER JOIN score s1 ON s.s_id = s1.s_id && s1.c_id = '01' INNER JOIN score s2 ON s.s_id = s2.s_id && s2.c_id = '02' WHERE s1.s_score > s2.s_score;
-- 2、查询"01"课程比"02"课程成绩低的学生的信息及课程分数 SELECT s.* ,s1.s_score '01score',s2.s_score '02score' FROM student s INNER JOIN score s1 ON s1.s_id = s.s_id && s1.c_id ='01' INNER JOIN score s2 ON s2.s_id = s.s_id && s2.c_id = '02' WHERE s1.s_score < s2.s_score;
-- 3、查询平均成绩大于等于60分的同学的学生编号和学生姓名和平均成绩 SELECT s.*, AVG(sc.s_score) 'avg' FROM student s INNER JOIN score sc ON sc.s_id = s.s_id GROUP BY s.s_id, s.s_name HAVING AVG(sc.s_score) >= 60;
-- 4、查询平均成绩小于60分的同学的学生编号和学生姓名和平均成绩 (包括有成绩的和无成绩的) SELECT s.*, AVG(IFNULL(sc.s_score,0)) 'avg' FROM student s INNER JOIN score sc ON sc.s_id = s.s_id GROUP BY s.s_id, s.s_name HAVING AVG(IFNULL(sc.s_score,0)) <= 60 ;
-- 5、查询所有同学的学生编号、学生姓名、选课总数、所有课程的总成绩 SELECT s.* ,SUM(sc.s_score) 'sumS' ,COUNT(sc.c_id) 'count' FROM student s INNER JOIN score sc ON sc.s_id = s.s_id GROUP BY s.s_id HAVING COUNT(sc.c_id) && SUM(sc.s_score);
-- 6、查询"李"姓老师的数量
SELECT COUNT(teacher.t_id) '数量' FROM teacher WHERE teacher.t_name LIKE '李%';
-- 7、查询学过"张三"老师授课的同学的信息 # 先查询张三老师的t_id,然后再找出score中t_id = 李老师id 的学习id, 然后根据id查询出学生信息
SELECT s.* FROM student s INNER JOIN score sc ON sc.s_id = s.s_id INNER JOIN course c ON c.c_id = sc.c_id INNER JOIN teacher t ON t.t_id = c.t_id WHERE t.t_name = '张三';
-- 8、查询没学过"张三"老师授课的同学的信息
SELECT * FROM student WHERE s_id not IN ( SELECT s.s_id FROM student s INNER JOIN score sc ON sc.s_id = s.s_id INNER JOIN course c ON sc.c_id = c.c_id INNER JOIN teacher t ON c.c_id = t.t_id WHERE t.t_name = '张三' );
-- 9、查询学过编号为"01"并且也学过编号为"02"的课程的同学的信息 SELECT s.* FROM student s INNER JOIN score sc1 ON sc1.s_id = s.s_id INNER JOIN score sc2 ON sc2.s_id = s.s_id WHERE sc1.c_id = '01' && sc2.c_id = '02';
-- 10、查询学过编号为"01"但是没有学过编号为"02"的课程的同学的信息
SELECT s.* FROM student s WHERE s.s_id IN (SELECT s_id FROM score WHERE c_id = '01') && s.s_id not IN (SELECT s_id FROM score WHERE c_id = '02');
-- 11、查询没有学全所有课程的同学的信息 # 总共有三个课程,只需要查询课程数不等于三的学生id即可得出 # SELECT COUNT(c_id) count1 FROM course; # SELECT COUNT(c_id) count2 FROM score WHERE s_id = 08; SELECT s.* FROM student s WHERE (SELECT COUNT(c_id) count1 FROM course) != (SELECT COUNT(c_id) count2 FROM score WHERE s_id = s.s_id);
-- 12、查询至少有一门课与学号为"01"的同学所学相同的同学的信息 # 直接查询一门都没有的 ,然后取反 -- SELECT s.c_id FROM score s -- WHERE s.s_id = '01' -- -- SELECT DISTINCT s.* -- FROM student s -- INNER JOIN score sc ON sc.s_id = s.s_id -- WHERE sc.c_id IN (SELECT c_id FROM score WHERE s_id = '01'); # ---------------------
SELECT * FROM student WHERE s_id NOT IN ( SELECT DISTINCT s.s_id FROM student s INNER JOIN score sc ON sc.s_id = s.s_id WHERE sc.c_id IN (SELECT c_id FROM score WHERE s_id = '01') );
-- 13、查询和"01"号的同学学习的课程完全相同的其他同学的信息 # 查询出01学生的选的课程为3个,所以直接找选的课程数为3 的
SELECT DISTINCT s.* FROM student s INNER JOIN score sc ON sc.s_id = s.s_id WHERE (SELECT COUNT(c_id) FROM score WHERE s_id = sc.s_id) = (SELECT COUNT(c_id) FROM score WHERE s_id = 01);
-- 14、查询没学过"张三"老师讲授的任一门课程的学生姓名 # 也就是根据张三的id ,查询选课中t_id有张三id的学生id ,然后在 not in 即可 SELECT s.s_name FROM Student s WHERE s.s_id NOT IN ( SELECT sc.s_id FROM Score sc JOIN Course c ON c.c_id = sc.c_id JOIN Teacher t ON t.t_id = c.t_id WHERE t.t_name = '张三' );
-- 15、查询两门及其以上不及格课程的同学的学号,姓名及其平均成绩
# 先查询不及格的学生然后按照学号分组,再求出数量大于等于2的学生,最后求平均成绩 SELECT s.s_id, s.s_name, AVG(sc.s_score) AS avg_score FROM Student s INNER JOIN Score sc ON s.s_id = sc.s_id WHERE sc.s_score < 60 GROUP BY s.s_id HAVING COUNT(*) >= 2;
-- 16、检索"01"课程分数小于60,按分数降序排列的学生信息
SELECT s.* FROM student s INNER JOIN score sc ON sc.s_id = s.s_id WHERE sc.c_id = '01' && sc.s_score <= 60 ORDER BY sc.s_score DESC;
-- 17、按平均成绩从高到低显示所有学生的所有课程的成绩以及平均成绩 SELECT sc.s_id, sc.s_score,AVG(sc.s_score) avg FROM score sc INNER JOIN course c ON sc.c_id = c.c_id GROUP BY sc.c_id, sc.s_id ORDER BY avg DESC;
-- 18.查询各科成绩最高分、最低分和平均分:以如下形式显示:课程ID,课程name,最高分,最低分,平均分,及格率,中等率,优良率,优秀率 -- 及格为>=60,中等为:70-80,优良为:80-90,优秀为:>=90 SELECT c.*, MAX(sc.s_score) max, MIN(sc.s_score) min , AVG(sc.s_score) avg , CONCAT(SUM(CASE WHEN sc.s_score >=60 THEN 1 ELSE 0 END) / COUNT(sc.c_id) * 100,'%') 及格率, CONCAT(SUM(CASE WHEN sc.s_score >=70 && sc.s_score < 80 THEN 1 ELSE 0 END) / COUNT(sc.c_id) * 100,'%') 中等率 , CONCAT(SUM(CASE WHEN sc.s_score >=80 && sc.s_score < 90 THEN 1 ELSE 0 END) / COUNT(sc.c_id) * 100,'%') 优良率 , CONCAT(SUM(CASE WHEN sc.s_score >= 90 THEN 1 ELSE 0 END) / COUNT(sc.c_id) * 100,'%') 优秀率 FROM course c INNER JOIN score sc ON sc.c_id = c.c_id GROUP BY sc.c_id; -- 19、按各科成绩进行排序,并显示排名(实现不完全) SELECT s1.s_id, s1.c_id, s1.s_score -- (COUNT(DISTINCT s2.s_score) + 1) rank FROM score s1 INNER JOIN score s2 ON s1.c_id = s2.c_id && s1.s_score > s2.s_score GROUP BY s1.s_id, s1.c_id, s1.s_score ORDER BY s1.c_id, s1.s_score DESC;
-- 20、查询学生的总成绩并进行排名 SELECT s.* , SUM(sc.s_score) sum, RANK() OVER(ORDER BY SUM(sc.s_score) DESC) 'rank' FROM student s INNER JOIN score sc ON sc.s_id = s.s_id GROUP BY s.s_id ORDER BY sum DESC;
-- 21、查询不同老师所教不同课程平均分从高到低显示
SELECT c.c_id ,c.t_id ,AVG(sc.s_score) avg FROM course c INNER JOIN score sc ON sc.c_id = c.c_id GROUP BY c.t_id , c.c_id ORDER BY avg DESC;
-- 22、查询所有课程的成绩第2名到第3名的学生信息及该课程成绩 SELECT s.* ,sc.c_id, c.c_name,sc.s_score FROM student s INNER JOIN score sc ON sc.s_id = s.s_id INNER JOIN course c ON c.c_id = sc.c_id WHERE ( SELECT COUNT(DISTINCT s_score) FROM Score WHERE c_id = c.c_id AND s_score > sc.s_score ) BETWEEN 1 AND 2 ORDER BY c.c_id, sc.s_score DESC;
-- 23、统计各科成绩各分数段人数:课程编号,课程名称,[100-85],[85-70],[70-60],[0-60]及所占百分比
SELECT c.c_id, c.c_name, COUNT(CASE WHEN s.s_score >= 85 AND s.s_score <= 100 THEN 1 END) AS '100-85', COUNT(CASE WHEN s.s_score >= 70 AND s.s_score < 85 THEN 1 END) AS '85-70', COUNT(CASE WHEN s.s_score >= 60 AND s.s_score < 70 THEN 1 END) AS '70-60', COUNT(CASE WHEN s.s_score >= 0 AND s.s_score < 60 THEN 1 END) AS '0-60', COUNT(*) AS total_count, CONCAT(COUNT(CASE WHEN s.s_score >= 85 AND s.s_score <= 100 THEN 1 END) * 100.0 / COUNT(*), '%') AS '100-85%', CONCAT(COUNT(CASE WHEN s.s_score >= 70 AND s.s_score < 85 THEN 1 END) * 100.0 / COUNT(*), '%') AS '85-70%', CONCAT(COUNT(CASE WHEN s.s_score >= 60 AND s.s_score < 70 THEN 1 END) * 100.0 / COUNT(*), '%') AS '70-60%', CONCAT(COUNT(CASE WHEN s.s_score >= 0 AND s.s_score < 60 THEN 1 END) * 100.0 / COUNT(*), '%') AS '0-60%' FROM Score s INNER JOIN Course c ON s.c_id = c.c_id GROUP BY c.c_id, c.c_name;
-- 24、查询学生平均成绩及其名次
SELECT s_id, AVG(s_score) AS avg_score, RANK() OVER (ORDER BY AVG(s_score) DESC) AS rank FROM Score GROUP BY s_id ORDER BY rank DESC;
-- 25、查询各科成绩前三名的记录 -- 1.选出b表比a表成绩大的所有组 -- 2.选出比当前id成绩大的 小于三个的 select a.c_id,a.s_id,a.s_score from score a left join score b on a.c_id = b.c_id and a.s_score<b.s_score group by a.s_id,a.c_id,a.s_score HAVING COUNT(b.s_id)<3 ORDER BY a.c_id,a.s_score DESC
-- 26、 查询每门课程被选修的学生数 SELECT sc.c_id, c.c_name,COUNT(sc.s_id) count FROM score sc INNER JOIN course c ON sc.c_id = c.c_id GROUP BY sc.c_id;
-- 27、查询出只有两门课程的全部学生的学号和姓名 SELECT s.* FROM student s INNER JOIN score sc ON sc.s_id = s.s_id GROUP BY s.s_id HAVING COUNT(sc.c_id) = 2;
-- 28、查询男生、女生人数 SELECT DISTINCT COUNT(s.s_id) '男', COUNT(s.s_id) '女' FROM student s GROUP BY s.s_sex;
-- 29、查询名字中含有"风"字的学生信息 SELECT s.* FROM student s WHERE s.s_name LIKE '%风%';
-- 30、查询同名同性学生名单,并统计同名人数 SELECT s_name, s_sex, COUNT(*) 'num' FROM student GROUP BY s_name, s_sex HAVING COUNT(*) > 1;
-- 31、查询1990年出生的学生名单 SELECT s.* FROM student s WHERE s.s_birth LIKE '%1990%';
-- 32、查询每门课程的平均成绩,结果按平均成绩降序排列,平均成绩相同时,按课程编号升序排列 SELECT sc.c_id , AVG(sc.s_score) avg FROM score sc GROUP BY sc.c_id ORDER BY avg DESC, sc.c_id ASC;
-- 33、查询平均成绩大于等于85的所有学生的学号、姓名和平均成绩 SELECT s.s_id ,s.s_name , AVG(sc.s_score) avg FROM student s INNER JOIN score sc ON sc.s_id = s.s_id GROUP BY s.s_id ,s.s_name HAVING AVG(sc.s_score) > 85;
-- 34、查询课程名称为"数学",且分数低于60的学生姓名和分数 SELECT c_id FROM course WHERE c_name = '数学'
SELECT s.s_id ,s.s_name, sc.c_id,sc.s_score FROM student s INNER JOIN score sc ON sc.s_id = s.s_id GROUP BY s.s_id, s.s_name, sc.c_id HAVING sc.c_id = (SELECT c_id FROM course WHERE c_name = '数学') && sc.s_score < 60;
-- 35、查询所有学生的课程及分数情况 SELECT s.s_id , s.s_name ,sc.c_id ,c.c_name,sc.s_score FROM student s INNER JOIN score sc ON sc.s_id = s.s_id INNER JOIN course c ON c.c_id = sc.c_id;
-- 36、查询任何一门课程成绩在70分以上的学生姓名、课程名称和分数; SELECT s.s_id ,s.s_name ,c.c_name ,sc.s_score FROM student s INNER JOIN score sc ON sc.s_id = s.s_id INNER JOIN course c ON c.c_id = sc.c_id WHERE sc.s_score >= 70;
-- 37、查询不及格的课程 SELECT s.s_id ,s.s_name ,c.c_name ,sc.s_score FROM student s INNER JOIN score sc ON sc.s_id = s.s_id INNER JOIN course c ON c.c_id = sc.c_id WHERE sc.s_score < 60; -- 38、查询课程编号为01且课程成绩在80分以上的学生的学号和姓名; SELECT s.*, sc.s_score FROM student s INNER JOIN score sc ON sc.s_id = s.s_id WHERE sc.c_id = '01' && sc.s_score >= 80;
-- 39、求每门课程的学生人数 SELECT c.c_id ,c.c_name , COUNT(sc.s_id) '人数' FROM course c INNER JOIN score sc ON sc.c_id = c.c_id GROUP BY c.c_id,c.c_name; -- 40、查询选修"张三"老师所授课程的学生中,成绩最高的学生信息及其成绩 SELECT s.s_id,s.s_name,sc.c_id, MAX(sc.s_score) max, sc.s_score FROM student s INNER JOIN score sc ON sc.s_id = s.s_id GROUP BY s.s_id, s.s_name, sc.c_id, sc.s_score HAVING sc.c_id = ( SELECT c_id FROM course WHERE t_id = ( SELECT t_id FROM teacher WHERE t_name = '张三') )LIMIT 1; # 两种方式 SELECT Student.s_id, Student.s_name, Score.s_score FROM Student JOIN Score ON Student.s_id = Score.s_id JOIN Course ON Score.c_id = Course.c_id JOIN Teacher ON Course.t_id = Teacher.t_id WHERE Teacher.t_name = '张三' ORDER BY Score.s_score DESC LIMIT 1;
-- 41、查询不同课程成绩相同的同一个学生的学生编号、课程编号、学生成绩 # 通过创建副本, 然后进行筛选 SELECT s1.s_id, sc1.c_id, sc1.s_score FROM Score sc1, Score sc2, Student s1, Student s2 WHERE sc1.s_id = s1.s_id AND sc2.s_id = s2.s_id AND sc1.s_id <> sc2.s_id AND sc1.c_id <> sc2.c_id AND sc1.s_score = sc2.s_score;
-- 42、查询每门功成绩最好的前两名 # 在where判断语句中进行判断 SELECT s1.c_id, s1.s_id, s1.s_score FROM Score s1 WHERE (SELECT COUNT(*) FROM Score s2 WHERE s2.c_id = s1.c_id AND s2.s_score > s1.s_score) < 2;
-- 43、统计每门课程的学生选修人数(超过5人的课程才统计)。要求输出课程号和选修人数,查询结果按人数降序排列,若人数相同,按课程号升序排列 SELECT sc.c_id,COUNT(sc.s_id) '人数' FROM score sc GROUP BY sc.c_id ORDER BY COUNT(sc.s_id) DESC ,sc.c_id ASC;
-- 44、检索至少选修两门课程的学生学号 SELECT sc.s_id ,COUNT(sc.c_id) 'num' FROM score sc GROUP BY sc.s_id HAVING COUNT(sc.c_id) >= 2;
-- 45、查询选修了全部课程的学生信息 SELECT s.* FROM score sc INNER JOIN student s WHERE s.s_id = sc.s_id GROUP BY sc.s_id HAVING COUNT(sc.c_id) = (SELECT COUNT(c_id) FROM course);
-- 46、查询各学生的年龄
# CURDATE() 函数返回当前日期,YEAR() 函数用于从日期中提取年份。DATEDIFF() 函数用于计算两个日期之间的天数差,然后将其与当前日期进行比较,以确定出生日期是否在当前日期之后。 # 如果出生日期在当前日期之后,则相差的年数需要减 1。 (DATEDIFF(CURDATE(), s.s_birth) < 0) SELECT s.* , YEAR(CURDATE()) - YEAR(s.s_birth) 'age' FROM student s; -- -- SELECT s.*, DATEDIFF(CURDATE(), s.s_birth) -- FROM student s ; SELECT s.*, YEAR(CURDATE()) - YEAR(s.s_birth) FROM student s ;
-- 47、查询本周过生日的学生 SELECT s_name, s_birth FROM Student WHERE WEEK(s_birth) = WEEK(CURDATE()) AND DATE_FORMAT(s_birth, '%m-%d') >= DATE_FORMAT(CURDATE(), '%m-%d') ORDER BY s_birth ASC;
-- 48、查询下周过生日的学生 SELECT s_name, s_birth FROM Student WHERE WEEK(s_birth) = WEEK(DATE_ADD(CURDATE(), INTERVAL 1 WEEK)) AND DATE_FORMAT(s_birth, '%m-%d') >= DATE_FORMAT(DATE_ADD(CURDATE(), INTERVAL 1 WEEK), '%m-%d') ORDER BY s_birth ASC; -- 49、查询本月过生日的学生
SELECT s_name, s_birth FROM Student WHERE MONTH(s_birth) = MONTH(CURDATE()) AND DATE_FORMAT(s_birth, '%d') >= DATE_FORMAT(CURDATE(), '%d') ORDER BY s_birth ASC; -- 50、查询下月过生日的学生 SELECT s_name, s_birth FROM Student WHERE MONTH(s_birth) = MONTH(DATE_ADD(CURDATE(), INTERVAL 1 MONTH)) AND DATE_FORMAT(s_birth, '%d') >= DATE_FORMAT(DATE_ADD(CURDATE(), INTERVAL 1 MONTH), '%d') ORDER BY s_birth ASC;
|