mysql实现每个专业分数段统计人数

我的表结构

student_info
| id |name |profession|score|
|--|--|--|--|
|id|姓名|分数|专业|

按分数段统计

400到500人数，300到400人数

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select
count(case when score between 400 and 500 then 1 end) as 400到500,
count(case when score between 300 and 400 then 1 end) as 300到400
from student_info;

按分数段和专业统计

400到500人数，300到400人数

select
count(case when score between 400 and 500 then 1 end) as 400到500,
count(case when score between 300 and 400 then 1 end) as 300到400
from student_info GROUP BY profession;

sql动态拼接生成

  int start = 200;
        int end = 700;
        int inter = 10;
        int count = (end-start)/inter;
        StringBuilder sqlBuilder = new StringBuilder();
        sqlBuilder.append("select ");
        for(int i =1;i<=count;i++){
            int next = start+inter-1;
            System.out.println(start + " \t" + next);
            sqlBuilder.append(" count(case when admission_score between ").append(start).append(" and ").append(next).append(" then 1 end) as ").append(start).append("到").append(next);
            if(i!=count){
                sqlBuilder.append(", ");
            }
            start += inter;
        }
        sqlBuilder.append(" from z_student_info");
        System.out.println(sqlBuilder.toString());

输出sql

select  count(case when admission_score between 200 and 209 then 1 end) as 200到209,  count(case when admission_score between 210 and 219 then 1 end) as 210到219,  count(case when admission_score between 220 and 229 then 1 end) as 220到229,  count(case when admission_score between 230 and 239 then 1 end) as 230到239,  count(case when admission_score between 240 and 249 then 1 end) as 240到249,  count(case when admission_score between 250 and 259 then 1 end) as 250到259,  count(case when admission_score between 260 and 269 then 1 end) as 260到269,  count(case when admission_score between 270 and 279 then 1 end) as 270到279,  count(case when admission_score between 280 and 289 then 1 end) as 280到289,  count(case when admission_score between 290 and 299 then 1 end) as 290到299,  count(case when admission_score between 300 and 309 then 1 end) as 300到309,  count(case when admission_score between 310 and 319 then 1 end) as 310到319,  count(case when admission_score between 320 and 329 then 1 end) as 320到329,  count(case when admission_score between 330 and 339 then 1 end) as 330到339,  count(case when admission_score between 340 and 349 then 1 end) as 340到349,  count(case when admission_score between 350 and 359 then 1 end) as 350到359,  count(case when admission_score between 360 and 369 then 1 end) as 360到369,  count(case when admission_score between 370 and 379 then 1 end) as 370到379,  count(case when admission_score between 380 and 389 then 1 end) as 380到389,  count(case when admission_score between 390 and 399 then 1 end) as 390到399,  count(case when admission_score between 400 and 409 then 1 end) as 400到409,  count(case when admission_score between 410 and 419 then 1 end) as 410到419,  count(case when admission_score between 420 and 429 then 1 end) as 420到429,  count(case when admission_score between 430 and 439 then 1 end) as 430到439,  count(case when admission_score between 440 and 449 then 1 end) as 440到449,  count(case when admission_score between 450 and 459 then 1 end) as 450到459,  count(case when admission_score between 460 and 469 then 1 end) as 460到469,  count(case when admission_score between 470 and 479 then 1 end) as 470到479,  count(case when admission_score between 480 and 489 then 1 end) as 480到489,  count(case when admission_score between 490 and 499 then 1 end) as 490到499,  count(case when admission_score between 500 and 509 then 1 end) as 500到509,  count(case when admission_score between 510 and 519 then 1 end) as 510到519,  count(case when admission_score between 520 and 529 then 1 end) as 520到529,  count(case when admission_score between 530 and 539 then 1 end) as 530到539,  count(case when admission_score between 540 and 549 then 1 end) as 540到549,  count(case when admission_score between 550 and 559 then 1 end) as 550到559,  count(case when admission_score between 560 and 569 then 1 end) as 560到569,  count(case when admission_score between 570 and 579 then 1 end) as 570到579,  count(case when admission_score between 580 and 589 then 1 end) as 580到589,  count(case when admission_score between 590 and 599 then 1 end) as 590到599,  count(case when admission_score between 600 and 609 then 1 end) as 600到609,  count(case when admission_score between 610 and 619 then 1 end) as 610到619,  count(case when admission_score between 620 and 629 then 1 end) as 620到629,  count(case when admission_score between 630 and 639 then 1 end) as 630到639,  count(case when admission_score between 640 and 649 then 1 end) as 640到649,  count(case when admission_score between 650 and 659 then 1 end) as 650到659,  count(case when admission_score between 660 and 669 then 1 end) as 660到669,  count(case when admission_score between 670 and 679 then 1 end) as 670到679,  count(case when admission_score between 680 and 689 then 1 end) as 680到689,  count(case when admission_score between 690 and 699 then 1 end) as 690到699 from z_student_info

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