mysql行列转换

myskya

原始插入数据如下：
5 B: Q2 m8 B, I* J, L1 ^要求查询结果如下 ：
: m& i4 I. W9 {

; k8 O: O' S' p! E创建数据库、表
& N; _) M$ T" i2 u2 ~' W) `

1. create database tests;
   ( V: Z, F" }3 w- f7 {# C2 W
2. use tests;
   # v# g! j3 P+ P' o: A: e
3. create table t_score(
   
4. id int primary key auto_increment,
   9 f4 E/ V3 y3 l% ]; Z. f
5. name varchar(20) not null,  #名字
   
6. Subject varchar(10) not null, #科目
   5 k/ a' g; x1 t' u4 N9 V: G! W4 k
7. Fraction double default 0  #分数
   * e! X/ |) s2 f% H% C+ l+ U! G. H
8. );

复制代码

添加数据

1. INSERT INTO `t_score`(name,Subject,Fraction) VALUES
   * U) ~  F( ^- e1 u* K
2.          ('王海', '语文', 86),
   6 D! K) q" B/ @5 e6 {
3.         ('王海', '数学', 83),
   6 G- k" V1 r2 E; C
4.         ('王海', '英语', 93),
   + t4 F9 _; @, \7 q
5.         ('陶俊', '语文', 88),
   ! {% p" a' d, U6 M
6.         ('陶俊', '数学', 84),
   5 M' i& A- `8 w& C; [
7.         ('陶俊', '英语', 94),
   2 s# S* x7 E/ A" m8 N- M4 D5 t
8.         ('刘可', '语文', 80),
   
9.         ('刘可', '数学', 86),
   
10.         ('刘可', '英语', 88),
    ' c$ L- j  u7 ?8 q
11.         ('李春', '语文', 89),
    
12.         ('李春', '数学', 80),
    . J" _+ f5 P% @7 d
13.         ('李春', '英语', 87);

复制代码

方式一:使用if

1. select name as 名字 ,
   
2. sum(if(Subject='语文',Fraction,0)) as 语文,
   # _! B# _/ L9 Z9 ]  p
3. sum(if(Subject='数学',Fraction,0))as 数学,
   1 I% K2 I6 t) ~$ U/ r9 z3 q0 [
4. sum(if(Subject='英语',Fraction,0))as 英语,
   5 N$ G6 F! U8 S2 _0 W7 R" h1 J
5. round(AVG(Fraction),2) as 平均分,
   
6. SUM(Fraction) as 总分
   9 M/ N/ z) O6 l+ z" v
7. from t_score group by name     
   
8. union
   1 I/ Q% J5 A* _. t( X. u8 e6 Q' L
9. select name as 名字 , sum(语文) Chinese,sum(数学) Math,sum(英语) English,round(AVG(总分),2)as 平均分,sum(总分) score  from(
   ! m0 X3 A) A& W7 n5 Q- O
10. select 'TOTAL' as name,
    - S! r3 G% Q3 h+ ?% \
11. sum(if(Subject='语文',Fraction,0)) as 语文,
    0 u( p) b3 S3 T, y1 g
12. sum(if(Subject='数学',Fraction,0))as 数学,
    
13. sum(if(Subject='英语',Fraction,0))as 英语,
    
14. SUM(Fraction) as 总分
    
15. from t_score group by Subject )t

复制代码

方式二:使用case

1. select  name as Name,
   0 u* F2 O; {( s: T: l1 ], q+ i0 x
2. sum(case when Subject = '语文' then Fraction end) as Chinese,
   3 |' Z0 [" g# P2 I1 _6 f
3. sum(case when Subject = '数学' then Fraction end) as Math,
   
4. sum(case when Subject = '英语' then Fraction end) as English,
   
5. sum(fraction)as score
   
6. from t_score group by name
   
7. UNION ALL
   
8. select  name as Name,sum(Chinese) as Chinese,sum(Math) as Math,sum(English) as English,sum(score) as score from(
   
9. select 'TOTAL' as name,
   
10. sum(case when Subject = '语文' then Fraction end) as Chinese,
    
11. sum(case when Subject = '数学' then Fraction end) as Math,
    
12. sum(case when Subject = '英语' then Fraction end) as English,
    2 C& o, D3 ^: J$ T. I; d+ Y4 d$ I( `
13. sum(fraction)as score
    
14. from t_score group by Subject)t

复制代码

方法三: with rollup

1. select
   ) M2 _2 |/ p: O( L; M& T5 Z
2.         ifnull(name,'TOll') name,
   , E6 _; r* w, @; l- f8 E
3.         sum(if(Subject='语文',Fraction,0)) as 语文,
   / F: Q8 i* G' N) _) P
4.        sum(if(Subject='英语',Fraction,0)) as 英语,
   9 ^) T& w; y; X- Y+ o: X
5.        sum(if(Subject='数学',Fraction,0))as 数学,
   
6.        sum(Fraction) 总分
   
7.         from t_score group by name with rollup

复制代码

查询结果如下：

; i& b* L  S2 H1 _" B4 d