mysql列转行



-- 创建表 学生表
CREATE TABLE `student` ( `stuid` VARCHAR(16) NOT NULL COMMENT '学号', `stunm` VARCHAR(20) NOT NULL COMMENT '学生姓名', PRIMARY KEY (`stuid`))COLLATE='utf8_general_ci'ENGINE=InnoDB;


-- 课程表

CREATE TABLE `courses` ( `courseno` VARCHAR(20) NOT NULL, `coursenm` VARCHAR(100) NOT NULL, PRIMARY KEY (`courseno`))COMMENT='课程表'COLLATE='utf8_general_ci'ENGINE=InnoDB;


-- 成绩表
CREATE TABLE `score` ( `stuid` VARCHAR(16) NOT NULL, `courseno` VARCHAR(20) NOT NULL, `scores` FLOAT NULL DEFAULT NULL, PRIMARY KEY (`stuid`, `courseno`))COLLATE='utf8_general_ci'ENGINE=InnoDB;

-- 插入数据

-- 学生表数据

Insert Into student (stuid, stunm) Values('1001', '张三');
Insert Into student (stuid, stunm) Values('1002', '李四');
Insert Into student (stuid, stunm) Values('1003', '赵二');
Insert Into student (stuid, stunm) Values('1004', '王五');
Insert Into student (stuid, stunm) Values('1005', '刘青');
Insert Into student (stuid, stunm) Values('1006', '周明');

-- 课程表数据
Insert Into courses (courseno, coursenm) Values('C001', '大学语文');
Insert Into courses (courseno, coursenm) Values('C002', '新视野英语');
Insert Into courses (courseno, coursenm) Values('C003', '离散数学');
Insert Into courses (courseno, coursenm) Values('C004', '概率论与数理统计');
Insert Into courses (courseno, coursenm) Values('C005', '线性代数');
Insert Into courses (courseno, coursenm) Values('C006', '高等数学(一)');
Insert Into courses (courseno, coursenm) Values('C007', '高等数学(二)');

-- 成绩表数据

Insert Into score(stuid, courseno, scores) Values('1001', 'C001', 67);
Insert Into score(stuid, courseno, scores) Values('1002', 'C001', 68);
Insert Into score(stuid, courseno, scores) Values('1003', 'C001', 69);
Insert Into score(stuid, courseno, scores) Values('1004', 'C001', 70);
Insert Into score(stuid, courseno, scores) Values('1005', 'C001', 71);
Insert Into score(stuid, courseno, scores) Values('1006', 'C001', 72);
Insert Into score(stuid, courseno, scores) Values('1001', 'C002', 87);
Insert Into score(stuid, courseno, scores) Values('1002', 'C002', 88);
Insert Into score(stuid, courseno, scores) Values('1003', 'C002', 89);
Insert Into score(stuid, courseno, scores) Values('1004', 'C002', 90);
Insert Into score(stuid, courseno, scores) Values('1005', 'C002', 91);
Insert Into score(stuid, courseno, scores) Values('1006', 'C002', 92);
Insert Into score(stuid, courseno, scores) Values('1001', 'C003', 83);
Insert Into score(stuid, courseno, scores) Values('1002', 'C003', 84);
Insert Into score(stuid, courseno, scores) Values('1003', 'C003', 85);
Insert Into score(stuid, courseno, scores) Values('1004', 'C003', 86);
Insert Into score(stuid, courseno, scores) Values('1005', 'C003', 87);
Insert Into score(stuid, courseno, scores) Values('1006', 'C003', 88);
Insert Into score(stuid, courseno, scores) Values('1001', 'C004', 88);
Insert Into score(stuid, courseno, scores) Values('1002', 'C004', 89);
Insert Into score(stuid, courseno, scores) Values('1003', 'C004', 90);
Insert Into score(stuid, courseno, scores) Values('1004', 'C004', 91);
Insert Into score(stuid, courseno, scores) Values('1005', 'C004', 92);
Insert Into score(stuid, courseno, scores) Values('1006', 'C004', 93);
Insert Into score(stuid, courseno, scores) Values('1001', 'C005', 77);
Insert Into score(stuid, courseno, scores) Values('1002', 'C005', 78);
Insert Into score(stuid, courseno, scores) Values('1003', 'C005', 79);

--
select st.stuid,st.stunm from student st select sc.stuid , sc.courseno,sc.scores from score sc select cs.courseno,cs.coursenm from courses cs

要求: 查询每个学生的 每门课程与每门成绩

select   st.stuid ID ,  st.stunm 姓名, cs.coursenm 课程名 ,sc.scores 成绩     from  student st, score sc ,courses cs

where st.stuid = sc.stuid and sc.courseno = cs.courseno 

select st.stuid 编号, st.stunm 姓名 ,
Max(case c.coursenm when '大学语文' then s.scores else 0 end ) '大学语文',
max(case c.coursenm when '新视野英语' then s.scores else 0 end) '新视野英语',
Max(case c.coursenm when '离散数学' then s.scores else 0 end) '离散数学',
MAX(case c.coursenm when '概率论与数理统计' then s.scores else 0 end) '概率论与数理统计',
MAX(case c.coursenm  when '线性代数' then s.scores else 0 end) '线性代数',
MAX(case c.coursenm when '高等数学(一)' then s.scores else 0 end) '高等数学(一)',
MAX(case c.coursenm when '高等数学(二)' then s.scores else 0 end) '高等数学(二)'
from  student st
LEFT JOIN score s on st.stuid = s.stuid
LEFT JOIN courses c on c.courseno = s.courseno
GROUP BY st.stuid