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

1. 查询课程ID为‘01’ 的课程的成绩第2名到第3名的学生信息及该课程成绩

SELECT　　d.*, c.排名, c.s_score, c.c_id FROM　　( SELECT a.s_id, a.s_score, a.c_id, @i:=@i+1 AS 排名 FROM score a,(SELECT @i:=0)s WHERE a.c_id='01' ORDER BY a.s_score DESC )c
LEFT JOIN 
    student d 
ON
    c.s_id = d.s_id
WHERE 
    排名 BETWEEN 2 AND 3

2. 查询课程ID为‘02’ 的课程的成绩第2名到第3名的学生信息及该课程成绩

SELECT
　　d.*, c.排名, c.s_score, c.c_id 
FROM
　　( SELECT a.s_id, a.s_score, a.c_id, @j:=@j+1 AS 排名 FROM score a,(SELECT @j:=0)s WHERE a.c_id='02' ORDER BY a.s_score DESC )c
LEFT JOIN 
    student d 
ON
    c.s_id = d.s_id
WHERE 
    排名 BETWEEN 2 AND 3

3. 查询课程ID为‘03’ 的课程的成绩第2名到第3名的学生信息及该课程成绩

SELECT
　　d.*, c.排名, c.s_score, c.c_id 
FROM
　　( SELECT a.s_id, a.s_score, a.c_id, @k:=@k+1 AS 排名 FROM score a,(SELECT @k:=0)s WHERE a.c_id='02' ORDER BY a.s_score DESC )c
LEFT JOIN 
    student d 
ON
    c.s_id = d.s_id
WHERE 
    排名 BETWEEN 2 AND 3

4. 联合

SELECT
　　d.*, c.排名, c.s_score, c.c_id 
FROM
　　( SELECT a.s_id, a.s_score, a.c_id, @i:=@i+1 AS 排名 FROM score a,(SELECT @i:=0)s WHERE a.c_id='02' ORDER BY a.s_score DESC )c
LEFT JOIN 
    student d 
ON
    c.s_id = d.s_id
WHERE 
    排名 BETWEEN 2 AND 3
UNION
SELECT
　　d.*, c.排名, c.s_score, c.c_id 
FROM
　　( SELECT a.s_id, a.s_score, a.c_id, @j:=@j+1 AS 排名 FROM score a,(SELECT @j:=0)s WHERE a.c_id='02' ORDER BY a.s_score DESC )c
LEFT JOIN 
    student d 
ON
    c.s_id = d.s_id
WHERE 
    排名 BETWEEN 2 AND 3
UNION
SELECT
　　d.*, c.排名, c.s_score, c.c_id 
FROM
　　( SELECT a.s_id, a.s_score, a.c_id, @k:=@k+1 AS 排名 FROM score a,(SELECT @k:=0)s WHERE a.c_id='02' ORDER BY a.s_score DESC )c
LEFT JOIN 
    student d 
ON
    c.s_id = d.s_id
WHERE 
    排名 BETWEEN 2 AND 3

5. 查询结果