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How does mysql count the number of people in each major score segment? The following will be introduced in detail by the editor.

1. My watch structure

Student_info | id | name | profession | score | |-| id | name | score | Specialty |

two。 Statistics by fractional segment

400 to 500 people, 300 to 400 people

Selectcount (case when score between 400 and 500 then 1 end) as 400 to 500 and count (case when score between 300 and 400 then 1 end) as 300 to 400from student_info

3. Statistics by score segment and specialty

400 to 500 people, 300 to 400 people

Selectcount (case when score between 400 and 500 then 1 end) as 400 to 500 and count (case when score between 300 and 400 then 1 end) as 300 to 400from student_info GROUP BY profession

4.sql dynamic splicing generation

Int start = 200; int end = 700; int inter = 10; int count = (end-start) / inter; StringBuilder sqlBuilder = new StringBuilder (); sqlBuilder.append ("select"); for (int I = 1teri

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