mysql 行列动态转换的实现(列联表,交叉表)

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 |
+---------+------+------+------+------+-------+

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;

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 ;