mysql行列转换

myskya

原始插入数据如下：
要求查询结果如下 ：
: U7 Z/ ?" D/ l: \

  ]: S; o  R. _! u8 K4 f" n% @- [创建数据库、表
! x3 \8 q! Y% F* `& k- P8 {

1. create database tests;
   
2. use tests;
   
3. create table t_score(
   
4. id int primary key auto_increment,
   & }3 Y! i+ n. E  T. k; i+ T
5. name varchar(20) not null,  #名字
   
6. Subject varchar(10) not null, #科目
   
7. Fraction double default 0  #分数
   
8. );

复制代码

添加数据

1. INSERT INTO `t_score`(name,Subject,Fraction) VALUES
   
2.          ('王海', '语文', 86),
   % r+ w% n( W  v9 w& }
3.         ('王海', '数学', 83),
   % _0 K$ p: a% b$ J, k
4.         ('王海', '英语', 93),
   
5.         ('陶俊', '语文', 88),
   
6.         ('陶俊', '数学', 84),
   
7.         ('陶俊', '英语', 94),
   $ o! w6 j! H( l3 g
8.         ('刘可', '语文', 80),
   
9.         ('刘可', '数学', 86),
   
10.         ('刘可', '英语', 88),
    ) `7 S) e7 r0 _
11.         ('李春', '语文', 89),
    5 j% f( e1 D! G+ u' a6 @* h& b9 ^% c
12.         ('李春', '数学', 80),
    2 R" ^2 m$ _2 R, c+ B
13.         ('李春', '英语', 87);

复制代码

方式一:使用if

1. select name as 名字 ,
   4 M7 k1 j6 D6 S$ X2 Q0 _$ g
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,
   
5. round(AVG(Fraction),2) as 平均分,
   
6. SUM(Fraction) as 总分
   
7. from t_score group by name     
   " n' }& F3 {$ _4 _) a7 v
8. union
   ) k  D$ b2 G4 O1 D! G
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,
    & a& q2 m+ ^6 j
12. sum(if(Subject='数学',Fraction,0))as 数学,
    
13. sum(if(Subject='英语',Fraction,0))as 英语,
    5 {9 s! O% A0 f# Z* ?0 N7 v+ a
14. SUM(Fraction) as 总分
    ' P- s8 l# k: d" w- F1 k) q. D
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,
   % q6 d3 M5 V: Z+ U
4. sum(case when Subject = '英语' then Fraction end) as English,
   ! m4 J+ e2 E) }/ Y
5. sum(fraction)as score
   
6. from t_score group by name
     `- M; ~( U; ?. U: Z2 z
7. UNION ALL
   ! V) g9 ?4 y  X
8. select  name as Name,sum(Chinese) as Chinese,sum(Math) as Math,sum(English) as English,sum(score) as score from(
   : H2 ^# {0 C5 b5 f9 d& e
9. select 'TOTAL' as name,
   0 F% j5 R& Z. M$ R+ k
10. sum(case when Subject = '语文' then Fraction end) as Chinese,
    7 `; B2 g9 J, Z4 z
11. sum(case when Subject = '数学' then Fraction end) as Math,
    4 P  k0 v: u' M2 a1 O* ]
12. sum(case when Subject = '英语' then Fraction end) as English,
    / [0 V2 q2 Q" Z6 Y
13. sum(fraction)as score
    - x3 D3 y$ J; v1 @' ^5 v
14. from t_score group by Subject)t

复制代码

方法三: with rollup

1. select
   
2.         ifnull(name,'TOll') name,
     O1 s" t8 y% j; k1 b8 H5 P) F6 K
3.         sum(if(Subject='语文',Fraction,0)) as 语文,
   6 |0 \9 ]) w( \, @+ K
4.        sum(if(Subject='英语',Fraction,0)) as 英语,
   
5.        sum(if(Subject='数学',Fraction,0))as 数学,
   & u+ q; }& C3 u, N
6.        sum(Fraction) 总分
   
7.         from t_score group by name with rollup

复制代码

查询结果如下：

1 O# m: C) }- m: c5 A, _
) b+ r9 h+ P- ~# e! n% p* ?' F3 j