发布于 2017-10-24 11:28:34 | 131 次阅读 | 评论: 0 | 来源: 网友投递
Mysql关系型数据库管理系统
MySQL是一个开放源码的小型关联式数据库管理系统，开发者为瑞典MySQL AB公司。MySQL被广泛地应用在Internet上的中小型网站中。由于其体积小、速度快、总体拥有成本低，尤其是开放源码这一特点，许多中小型网站为了降低网站总体拥有成本而选择了MySQL作为网站数据库。
（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 ;以上这篇mysql 行列动态转换的实现(列联表,交叉表)就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持PHPERZ。