mysql行列转换

myskya

原始插入数据如下：
要求查询结果如下 ：
. N# ?! N8 f- g' s( O/ b% X

创建数据库、表
7 I: ?- o( X1 s4 |% W5 _7 Q" C

1. create database tests;
   
2. use tests;
   
3. create table t_score(
   9 i6 m/ m! P! i
4. id int primary key auto_increment,
   
5. name varchar(20) not null,  #名字
   
6. Subject varchar(10) not null, #科目
   ) n8 O2 x) E* `
7. Fraction double default 0  #分数
   + \7 O- b: R# N! }1 \6 B2 a
8. );

复制代码

添加数据

1. INSERT INTO `t_score`(name,Subject,Fraction) VALUES
   / |1 y# `* i6 O# c8 K
2.          ('王海', '语文', 86),
   
3.         ('王海', '数学', 83),
   4 s' u# l" E1 J) X* A
4.         ('王海', '英语', 93),
   
5.         ('陶俊', '语文', 88),
   
6.         ('陶俊', '数学', 84),
   
7.         ('陶俊', '英语', 94),
   - Y6 @: b8 d# p& q! \# c
8.         ('刘可', '语文', 80),
   & @" _8 u6 y. j2 ^$ r+ B8 o) j6 J
9.         ('刘可', '数学', 86),
   7 N0 r% ^8 f- a& _2 I6 s6 m
10.         ('刘可', '英语', 88),
    
11.         ('李春', '语文', 89),
    + j2 |1 B! _' H9 M2 `) o
12.         ('李春', '数学', 80),
    7 a" l2 }" n6 h! w
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,
   
3. sum(if(Subject='数学',Fraction,0))as 数学,
   
4. sum(if(Subject='英语',Fraction,0))as 英语,
   + Y& k3 O% b0 Y# J! y
5. round(AVG(Fraction),2) as 平均分,
   
6. SUM(Fraction) as 总分
   + r0 l# b2 K8 a7 O* {
7. from t_score group by name     
   ; u; g0 `* x7 B9 G% v1 L0 C. h% K
8. union
   + f3 Z7 s6 {/ s
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(
   
10. select 'TOTAL' as name,
    
11. sum(if(Subject='语文',Fraction,0)) as 语文,
    
12. sum(if(Subject='数学',Fraction,0))as 数学,
      E1 x: ?. L1 s' d
13. sum(if(Subject='英语',Fraction,0))as 英语,
    - Z% g$ `2 l7 I; Z
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,
   
2. sum(case when Subject = '语文' then Fraction end) as Chinese,
   
3. sum(case when Subject = '数学' then Fraction end) as Math,
   8 {, H- e3 {8 V& m) o$ K
4. sum(case when Subject = '英语' then Fraction end) as English,
   1 I0 M! k- E, c0 y( m, O
5. sum(fraction)as score
   
6. from t_score group by name
   6 V. [- s6 R; J# y: ?" e
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,
   & e" P$ Z. d/ b! ^/ y2 m+ w
10. sum(case when Subject = '语文' then Fraction end) as Chinese,
    
11. sum(case when Subject = '数学' then Fraction end) as Math,
    / c# K: ?7 k8 E' I4 V0 ^! v' Q
12. sum(case when Subject = '英语' then Fraction end) as English,
    / W, R2 Z& _% ], A
13. sum(fraction)as score
    
14. from t_score group by Subject)t

复制代码

方法三: with rollup

1. select
   
2.         ifnull(name,'TOll') name,
   
3.         sum(if(Subject='语文',Fraction,0)) as 语文,
   - C) N$ ?$ B; T! N% o
4.        sum(if(Subject='英语',Fraction,0)) as 英语,
   
5.        sum(if(Subject='数学',Fraction,0))as 数学,
   ( x' ^: k4 n4 c2 Z9 r" k8 L
6.        sum(Fraction) 总分
   
7.         from t_score group by name with rollup

复制代码

查询结果如下：