mysql 行列动态转换（列联表，交叉表）

（1）动态，适用于列不确定情况

create table table_name(

 id int primary key,

 col1 char(2),

 col2 char(2),

 col3 int

);

insert into table_name values

(1 ,'A1','B1',9),

(2 ,'A2','B1',7),

(3 ,'A3','B1',4),

(4 ,'A4','B1',2),

(5 ,'A1','B2',2),

(6 ,'A2','B2',9),

(7 ,'A3','B2',8),

(8 ,'A4','B2',5),

(9 ,'A1','B3',1),

(10 ,'A2','B3',8),

(11 ,'A3','B3',8),

(12 ,'A4','B3',6),

(13 ,'A1','B4',8),

(14 ,'A2','B4',2),

(15 ,'A3','B4',6),

(16 ,'A4','B4',9),

(17 ,'A1','B4',3),

(18 ,'A2','B4',5),

(19 ,'A3','B4',2),

(20 ,'A4','B4',5);

select * from table_name;

+----+------+------+------+

| id | col1 | col2 | col3 |

+----+------+------+------+

|  1 | A1   | B1   |    9 |

|  2 | A2   | B1   |    7 |

|  3 | A3   | B1   |    4 |

|  4 | A4   | B1   |    2 |

|  5 | A1   | B2   |    2 |

|  6 | A2   | B2   |    9 |

|  7 | A3   | B2   |    8 |

|  8 | A4   | B2   |    5 |

|  9 | A1   | B3   |    1 |

| 10 | A2   | B3   |    8 |

| 11 | A3   | B3   |    8 |

| 12 | A4   | B3   |    6 |

| 13 | A1   | B4   |    8 |

| 14 | A2   | B4   |    2 |

| 15 | A3   | B4   |    6 |

| 16 | A4   | B4   |    9 |

| 17 | A1   | B4   |    3 |

| 18 | A2   | B4   |    5 |

| 19 | A3   | B4   |    2 |

| 20 | A4   | B4   |    5 |

+----+------+------+------+

SET @EE='';

SELECT @EE:=CONCAT(@EE,'SUM(IF(col2=\'',col2,'\'',',col3,0)) AS ',col2,',') FROM (SELECT DISTINCT col2 FROM table_name) A;

SET @QQ=CONCAT('SELECT ifnull(col1,\'total\') AS columnA,',LEFT(@EE,LENGTH(@EE)-1),' ,SUM(col3) AS TOTAL FROM table_name GROUP BY col1 WITH ROLLUP');

PREPARE stmt2 FROM @QQ;

EXECUTE stmt2;

+---------+------+------+------+------+-------+

| columnA | B1   | B2   | B3   | B4   | TOTAL |

+---------+------+------+------+------+-------+

| A1      |    9 |    2 |    1 |   11 |    23 |

| A2      |    7 |    9 |    8 |    7 |    31 |

| A3      |    4 |    8 |    8 |    8 |    28 |

| A4      |    2 |    5 |    6 |   14 |    27 |

| total   |   22 |   24 |   23 |   40 |   109 |

+---------+------+------+------+------+-------+

 

（2）第二个字段确定的情况下使用

SELECT

   IFNULL(col1,'total') AS total,

   SUM(IF(col2='B1',col3,0)) AS B1,

   SUM(IF(col2='B2',col3,0)) AS B2,

   SUM(IF(col2='B3',col3,0)) AS B3,

   SUM(IF(col2='B4',col3,0)) AS B4,

   SUM(IF(col2='total',col3,0)) AS total

 FROM (

   SELECT col1,IFNULL(col2,'total') AS col2,SUM(col3) AS col3

   FROM table_name

   GROUP BY col1,col2

   WITH ROLLUP

   HAVING col1 IS NOT NULL

 ) AS A

 GROUP BY col1

 WITH ROLLUP;

 

注：  WITH ROLLUP 用于列上求和；  SUM(IF(col2='total',col3,0)) AS total 用于行上求和。

 

（3）第二个字段确定的情况下使用

 select ifnull(col1,'total') AS col1,

 sum(if(col2='B1',col3,0)) AS B1,

 sum(if(col2='B2',col3,0)) AS B2,

 sum(if(col2='B3',col3,0)) AS B3,

 sum(if(col2='B4',col3,0)) AS B4,SUM(col3) AS TOTAL

 from table_name

 group by col1 with rollup ;

 

REF:

http://blog.chinaunix.net/uid-7692530-id-2567582.html