如何获得具有条件的行数

Question

我有一张这样的桌子

id   student teacher
10       a       b
11       c       b
12       d       c
13       e       b

学生“e”是第3名学生，老师是“b”。 如何通过一个查询得到这个？

Answer 1

你可以这样做：

SELECT * FROM (
   SELECT @row := @row + 1 as row, t.* FROM student_table t, (SELECT @row := 0) r where t.teacher ='b'
) s where student = 'e'

Answer 2

非常接近Secator的帖子

SELECT *
FROM (
    SELECT (@row := @row + 1) AS rank, student
    FROM my_table,
    (SELECT @row := 0) q
    WHERE teacher = 'b'
) s
WHERE student = 'e'