Mysql实现行列转换

 1 -- Step1:建表并插入数据
 2 
 3 -- Step2:中间转换，即“二维转一维”得到一维表。
 4 
 5 -- Step3:利用IF判断并“group by”即可得到目标结果表。
 6 
 7  
 8 
 9 -- 加载
10 
11 use test;
12 
13 create table score (
14 
15 name varchar(11),
16 
17 Math int,
18 
19 English int
20 
21 );
22 
23 insert into score values(‘甲‘,89,78);
24 
25 insert into score values(‘乙‘,77,81);
26 
27 insert into score values(‘丙‘,87,98);
28 
29  
30 
31 -- 查询生成目标表
32 
33 SELECT
34 
35 c2 AS ‘课程‘,
36 
37 SUM(IF(c1=‘甲‘,c3,0)) AS ‘甲‘,
38 
39 SUM(IF(c1=‘乙‘,c3,0)) AS ‘乙‘,
40 
41 SUM(IF(c1=‘丙‘,c3,0)) AS ‘丙‘ from(
42 
43 select name as c1,‘Math‘ as c2,Math as c3 from score group by name
44 
45 Union 
46 
47 select name,‘English‘ as c2,English from score group  by name
48 
49 ) AS tx group by c2;
50 
51  
52