mysql行列转换

myskya

原始插入数据如下：
- j: E: k" v0 r1 z" V% }# |. F% W要求查询结果如下 ：
! f/ W0 Z# n+ o' e; W

创建数据库、表

1. create database tests;
   
2. use tests;
   
3. create table t_score(
   $ M3 Y2 S1 N& q! q! o5 T# G
4. id int primary key auto_increment,
   
5. name varchar(20) not null,  #名字
   # o' q7 M, e: _' f  x5 Y& _7 ?
6. Subject varchar(10) not null, #科目
   
7. Fraction double default 0  #分数
   
8. );

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添加数据

1. INSERT INTO `t_score`(name,Subject,Fraction) VALUES
   
2.          ('王海', '语文', 86),
   ( x6 }7 `* f+ u0 [
3.         ('王海', '数学', 83),
   
4.         ('王海', '英语', 93),
   
5.         ('陶俊', '语文', 88),
   5 R/ V" g* x' l. C
6.         ('陶俊', '数学', 84),
   1 Y: R- D- ^- ?
7.         ('陶俊', '英语', 94),
   
8.         ('刘可', '语文', 80),
   
9.         ('刘可', '数学', 86),
   
10.         ('刘可', '英语', 88),
    4 Q0 d  R; \- f9 @* K, c" b; A1 l
11.         ('李春', '语文', 89),
    
12.         ('李春', '数学', 80),
    - t0 r: e2 D1 D. D2 K% e5 A; Y  W) |
13.         ('李春', '英语', 87);

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方式一:使用if

1. select name as 名字 ,
   
2. sum(if(Subject='语文',Fraction,0)) as 语文,
   0 Z. H6 F) A* {4 u9 O
3. sum(if(Subject='数学',Fraction,0))as 数学,
   * [: p' Q3 `' n2 \, t! u) W
4. sum(if(Subject='英语',Fraction,0))as 英语,
   , p6 K( m: I  i. X8 ^; a
5. round(AVG(Fraction),2) as 平均分,
   # q5 F! l( k9 Q- p
6. SUM(Fraction) as 总分
   
7. from t_score group by name     
   
8. union
   + z; W6 ~, r6 V) }
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,
    
13. sum(if(Subject='英语',Fraction,0))as 英语,
    . u2 [5 C: k4 M( O5 I4 ~
14. SUM(Fraction) as 总分
    ) l- G# V& W/ N4 I. O
15. from t_score group by Subject )t

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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,
   
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(
   : n4 J4 J( _9 l- X
9. select 'TOTAL' as name,
   6 r; r! t7 x2 L" k5 k( [
10. sum(case when Subject = '语文' then Fraction end) as Chinese,
    ( I1 A; V- \' z# ]( Q
11. sum(case when Subject = '数学' then Fraction end) as Math,
    
12. sum(case when Subject = '英语' then Fraction end) as English,
    
13. sum(fraction)as score
    % q7 K) b2 s& f, J' T5 L
14. from t_score group by Subject)t

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方法三: with rollup

1. select
   
2.         ifnull(name,'TOll') name,
   
3.         sum(if(Subject='语文',Fraction,0)) as 语文,
   $ c) v" M6 E" W
4.        sum(if(Subject='英语',Fraction,0)) as 英语,
   6 d1 N: X* Y3 c' _( ~5 Y. v
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

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查询结果如下：

. H- @# ]6 M2 A/ f+ M/ A5 B
( u7 X7 x' s0 U, h