MySQL 行列转换变化各种方法实现总结（行变列报表统计列变行数据记录统计等）

前言：

mysql行列变化，最难的就是将多个列变成多行，使用的比较多的是统计学中行变列，列变行，没有找到现成的函数或者语句，所以自己写了存储过程，使用动态sql来实现，应用业务场景，用户每个月都有使用记录数录入一张表，一个月一个字段，所以表的字段是动态增长的，现在需要实时统计当前用户使用的总数量，如果你知道有多少个字段，那么可以用select c1+c2+c3+…. From tbname where tid=’111’;来实现，但是关键是这个都是动态的，所以在应用程序端来实现确实不适宜，可以放在数据库后台在存储过程里实现。

而且在行变成列中，如果要写单个sql来实现，列的数目就需要写死，因为如果不知道要展示成多少列的话，就需要用动态变量，而一条sql里面无法使用动态变量。但是可以使用sql块来实现动态的效果。

一，列变成行例子演示

1，准备测试数据

这是基础数据表，里面有多个字段wm201403……，现在需要把N个这样的列变成行数据。

USE csdn;DROP TABLE IF EXISTS flow_table;CREATE TABLE `flow_table` (  `ID` INT(11) NOT NULL AUTO_INCREMENT,  `Number` BIGINT(11) NOT NULL,  `City` VARCHAR(10) NOT NULL,  `wm201403` DECIMAL(7,2) DEFAULT NULL,  `wm201404` DECIMAL(7,2) DEFAULT NULL,  `wm201405` DECIMAL(7,2) DEFAULT NULL,  `wm201406` DECIMAL(7,2) DEFAULT NULL,  `wm201407` DECIMAL(7,2) DEFAULT NULL,  `wm201408` DECIMAL(7,2) DEFAULT NULL,  PRIMARY KEY (`ID`,`Number`)) ENGINE=INNODB   DEFAULT CHARSET=utf8;

录入一批测试数据：

INSERT INTO flow_table(Number,City,wm201403,wm201404,wm201405,wm201406,wm201407,wm201408)SELECT 1,'shanghai',100.2,180.4,141,164,124,127;INSERT INTO flow_table(Number,City,wm201403,wm201404,wm201405,wm201406,wm201407,wm201408)SELECT 2,'shanghai',110.23,180.34,141.23,104.78,124.67,127.45;INSERT INTO flow_table(Number,City,wm201403,wm201404,wm201405,wm201406,wm201407,wm201408)SELECT 3,'beijing',123.23,110.34,131.33,154.58,154.67,167.45;INSERT INTO flow_table(Number,City,wm201403,wm201404,wm201405,wm201406,wm201407,wm201408)SELECT 4,'hangzhou',0,110.34,131.33,154.58,154.67,0;INSERT INTO flow_table(Number,City,wm201405,wm201406,wm201407,wm201408)SELECT 5,'hangzhou',131.33,154.58,154.67,0;

需要达到的统计效果是：

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

| Number | total_num |

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

| 1 | 836.60 |

| 2 | 788.70 |

| 3 | 841.60 |

| 4 | 550.92 |

| 5 | 440.58 |

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

5 rows in set (0.00 sec)

2，存储过程遍历：

这个存储过程建立了2张临时表，查询测试表数据形成游标，遍历游标根据主键Number来调用pro_flow_modify存储过程进行行列变化。代码如下：

DELIMITER $$DROP PROCEDURE IF EXISTS csdn.`proc_all_changes`$$CREATE PROCEDURE csdn.proc_all_changes()BEGIN    DECLARE v_number BIGINT;    DECLARE v_city VARCHAR(10);    DECLARE _done INT DEFAULT 0;         /*定义游标*/    DECLARE cur_all CURSOR FOR SELECT Number,City FROM csdn.`flow_table`;    /**这里如果需要定义下当NOT FOUND的时候，EXIT退出游标遍历，不然如果设置成CONTINUE会一直执行下去。*/    DECLARE EXIT HANDLER FOR NOT FOUND BEGIN SET _done=1;END;                 /*建立临时表，存放所有字段的临时表*/ DROP TABLE IF EXISTS flow_n_columns; CREATE TABLE `flow_n_columns` (   `column_name` VARCHAR(10) NOT NULL ) ENGINE=INNODB DEFAULT CHARSET=utf8; /*存放最终变成行的数据表*/ DROP TABLE IF EXISTS flow_tmp; CREATE TABLE `flow_tmp` (   `Number` INT(11) DEFAULT NULL,   `City` VARCHAR(10) DEFAULT NULL,   `wm_str` VARCHAR(10) DEFAULT NULL,   `Wm` DECIMAL(7,2) DEFAULT NULL ) ENGINE=INNODB DEFAULT CHARSET=utf8;    OPEN cur_all;    REPEAT        FETCH cur_all INTO v_number, v_city;        IF NOT _done THEN   CALL csdn.pro_flow_modify(v_number,v_city);        END IF;         UNTIL _done=1 END REPEAT;    CLOSE cur_all;      /*展示下所有的行转列的数据**/ SELECT * FROM csdn.flow_tmp;      END$$   DELIMITER ;

3，行里变化存储过程

通过查询系统表information_schema.`COLUMNS`来获取测试表flow_table的所有列，然后写动态SQL，来把列的值录入到临时表flow_tmp中。

DELIMITER $$DROP PROCEDURE IF EXISTS csdn.`pro_flow_modify`$$CREATE PROCEDURE csdn.`pro_flow_modify`(p_Number INT,p_city VARCHAR(10))BEGIN DECLARE v_column_name VARCHAR(10) DEFAULT ''; DECLARE v_exe_sql VARCHAR(1000) DEFAULT ''; DECLARE v_start_wm VARCHAR(10) DEFAULT ''; DECLARE v_end_wm VARCHAR(10) DEFAULT ''; DECLARE v_num  DECIMAL(10,2) DEFAULT 0;  DECLARE i INT DEFAULT 1; DECLARE v_Number INT DEFAULT 0; SET v_Number=p_Number;  DELETE FROM csdn.flow_n_columns; DELETE FROM csdn.flow_tmp WHERE Number=v_Number;   /*把测试表flow_table的所有字段都录入字段临时表中，这样就达到了从列变成行的目的*/ INSERT INTO flow_n_columns SELECT t.`COLUMN_NAME` FROM information_schema.`COLUMNS` t WHERE t.`TABLE_NAME`='flow_table' AND t.`TABLE_SCHEMA`='csdn' AND t.`COLUMN_NAME` NOT IN('ID','Number','City'); SELECT column_name INTO v_column_name FROM csdn.flow_n_columns LIMIT 1;  /*开始循环遍历字段临时表的字段数据，并且把字段值放入临时表flow_tmp里面*/ WHILE i>0 DO  SET v_exe_sql=CONCAT('INSERT INTO csdn.flow_tmp(Number,City,wm_str,Wm) select ',v_Number,',\'',p_city, '\',\'',v_column_name,'\',',v_column_name,' from csdn.flow_table WHERE flow_table.Number=',v_Number,';');  SET @sql=v_exe_sql;  PREPARE s1 FROM @sql;  EXECUTE s1;  DEALLOCATE PREPARE s1;   DELETE FROM csdn.flow_n_columns WHERE column_name=v_column_name;  SELECT column_name INTO v_column_name FROM csdn.flow_n_columns LIMIT 1;  SELECT COUNT(1) INTO i FROM csdn.flow_n_columns ;  DELETE FROM csdn.flow_tmp WHERE Wm=0; END WHILE; /*由于触发器是不支持动态sql，所以不能使用while循环，动态遍历所有统计列的，只能写死列了，如下所示： 现在一个个insert只能写死了, flow_table表有多少个统计列就写多少个insert sql，以后新添加一个列，就在这里新添加一条insertsql语句 INSERT INTO flow_tmp(Number,City,wm_str,Wm) SELECT v_Number,p_city,'wm201403',wm201403 FROM flow_table WHERE Number=v_Number ; INSERT INTO flow_tmp(Number,City,wm_str,Wm) SELECT v_Number,p_city,'wm201404',wm201404 FROM flow_table WHERE Number=v_Number ; INSERT INTO flow_tmp(Number,City,wm_str,Wm) SELECT v_Number,p_city,'wm201405',wm201405 FROM flow_table WHERE Number=v_Number ; INSERT INTO flow_tmp(Number,City,wm_str,Wm) SELECT v_Number,p_city,'wm201406',wm201406 FROM flow_table WHERE Number=v_Number ; INSERT INTO flow_tmp(Number,City,wm_str,Wm) SELECT v_Number,p_city,'wm201407',wm201407 FROM flow_table WHERE Number=v_Number ; INSERT INTO flow_tmp(Number,City,wm_str,Wm) SELECT v_Number,p_city,'wm201408',wm201408 FROM flow_table WHERE Number=v_Number ; */  /*清除掉不数据=0的列*/ DELETE FROM csdn.flow_tmp WHERE Wm=0 OR Wm IS NULL;  SELECT wm_str INTO v_start_wm FROM csdn.flow_tmp WHERE Number=v_Number ORDER BY wm_str ASC LIMIT 1; SELECT wm_str INTO v_end_wm FROM csdn.flow_tmp WHERE Number=v_Number ORDER BY wm_str DESC LIMIT 1; SELECT SUM(Wm) INTO v_num FROM csdn.flow_tmp WHERE Number=v_Number;      END$$DELIMITER ;

4，列变行结果展示

临时表的所有数据：

mysql> SELECT * FROM csdn.flow_tmp;+--------+----------+----------+--------+| Number | City     | wm_str   | Wm     |+--------+----------+----------+--------+|      1 | shanghai | wm201403 | 100.20 ||      1 | shanghai | wm201404 | 180.40 ||      1 | shanghai | wm201405 | 141.00 ||      1 | shanghai | wm201406 | 164.00 ||      1 | shanghai | wm201407 | 124.00 ||      1 | shanghai | wm201408 | 127.00 ||      2 | shanghai | wm201403 | 110.23 ||      2 | shanghai | wm201404 | 180.34 ||      2 | shanghai | wm201405 | 141.23 ||      2 | shanghai | wm201406 | 104.78 ||      2 | shanghai | wm201407 | 124.67 ||      2 | shanghai | wm201408 | 127.45 ||      3 | beijing  | wm201403 | 123.23 ||      3 | beijing  | wm201404 | 110.34 ||      3 | beijing  | wm201405 | 131.33 ||      3 | beijing  | wm201406 | 154.58 ||      3 | beijing  | wm201407 | 154.67 ||      3 | beijing  | wm201408 | 167.45 ||      4 | hangzhou | wm201404 | 110.34 ||      4 | hangzhou | wm201405 | 131.33 ||      4 | hangzhou | wm201406 | 154.58 ||      4 | hangzhou | wm201407 | 154.67 ||      5 | hangzhou | wm201405 | 131.33 ||      5 | hangzhou | wm201406 | 154.58 ||      5 | hangzhou | wm201407 | 154.67 |+--------+----------+----------+--------+25 rows in set (0.00 sec)mysql>

统计每个用户的使用总量为：

mysql> SELECT Number,SUM(Wm) 'total_num' FROM flow_tmp GROUP BY Number ORDER BY Number;+--------+-----------+| Number | total_num |+--------+-----------+|      1 |    836.60 ||      2 |    788.70 ||      3 |    841.60 ||      4 |    550.92 ||      5 |    440.58 |+--------+-----------+5 rows in set (0.00 sec)mysql>

二，行变列例子演示

1，准备测试数据

USE csdn;DROP TABLE IF EXISTS csdn.tb;CREATE TABLE tb(`cname` VARCHAR(10),cource VARCHAR(10),score INT) ENGINE=INNODB;INSERT INTO tb VALUES('张三','语文',74);INSERT INTO tb VALUES('张三','数学',83);INSERT INTO tb VALUES('张三','物理',93);INSERT INTO tb VALUES('李四','语文',74);INSERT INTO tb VALUES('李四','数学',84);INSERT INTO tb VALUES('李四','物理',94);SELECT * FROM tb;

需要得到的结果是：

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

| 姓名 | 语文 | 数学 | 物理 | 总成绩 | 平均成绩 |

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

| 张三 | 74.00 | 83.00 | 93.00 | 250.00 | 83.33 |

| 李四 | 74.00 | 84.00 | 94.00 | 252.00 | 84.00 |

| 总成绩平均数 | 74.00 | 83.50 | 93.50 | 251.00 | 83.67 |

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

2，利用SUM(IF()) 生成列 + WITH ROLLUP 生成汇总行,并利用 IFNULL将汇总行标题显示为 Total_num

SQL代码块如下：

SELECT cname AS "姓名", SUM(IF(cource="语文",score,0)) AS "语文", SUM(IF(cource="数学",score,0)) AS "数学", SUM(IF(cource="物理",score,0)) AS "物理", SUM(score) AS "总成绩", ROUND(AVG(score),2) AS "平均成绩"FROM tb GROUP BY cnameUNION ALLSELECT "总成绩平均数", ROUND(AVG(`语文`),2) , ROUND(AVG(`数学`),2), ROUND(AVG(`物理`),2), ROUND(AVG(`总成绩`),2), ROUND(AVG(`平均成绩`),2)FROM( SELECT "all",cname AS "姓名",  SUM(IF(cource="语文",score,0)) AS "语文",  SUM(IF(cource="数学",score,0)) AS "数学",  SUM(IF(cource="物理",score,0)) AS "物理",  SUM(score) AS "总成绩",  AVG(score) AS "平均成绩" FROM tb  GROUP BY cname)tb2 GROUP BY tb2.all;

执行结果正确，如下所示：

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

| 姓名 | 语文 | 数学 | 物理 | 总成绩 | 平均成绩 |

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

| 张三 | 74.00 | 83.00 | 93.00 | 250.00 | 83.33 |

| 李四 | 74.00 | 84.00 | 94.00 | 252.00 | 84.00 |

| 总成绩平均数 | 74.00 | 83.50 | 93.50 | 251.00 | 83.67 |

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

3，利用max(CASE ... WHEN ... THEN .. ELSE END) AS "语文"的方式来实现

SQL代码如下：

SELECT  cname AS "姓名", MAX(CASE cource WHEN "语文" THEN score ELSE 0 END) AS "语文",  MAX(CASE cource WHEN "数学" THEN score ELSE 0 END) AS "数学",  MAX(CASE cource WHEN "物理" THEN score ELSE 0 END) AS "物理",  SUM(score) AS "总成绩", ROUND(AVG(score) ,2) AS "平均成绩"FROM tb GROUP BY `cname`UNION ALLSELECT "总成绩平均数", ROUND(AVG(`语文`),2) , ROUND(AVG(`数学`),2), ROUND(AVG(`物理`),2), ROUND(AVG(`总成绩`),2), ROUND(AVG(`平均成绩`),2)FROM( SELECT 'all' ,    cname AS "姓名",  MAX(CASE cource WHEN "语文" THEN score ELSE 0 END) AS "语文",   MAX(CASE cource WHEN "数学" THEN score ELSE 0 END) AS "数学",   MAX(CASE cource WHEN "物理" THEN score ELSE 0 END) AS "物理",   SUM(score) AS "总成绩",  ROUND(AVG(score) ,2) AS "平均成绩" FROM tb  GROUP BY `cname` )tb2 GROUP BY tb2.all

执行结果正确，如下所示：

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

| 姓名 | 语文 | 数学 | 物理 | 总成绩 | 平均成绩 |

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

| 张三 | 74.00 | 83.00 | 93.00 | 250.00 | 83.33 |

| 李四 | 74.00 | 84.00 | 94.00 | 252.00 | 84.00 |

| 总成绩平均数 | 74.00 | 83.50 | 93.50 | 251.00 | 83.67 |

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

4，利用 WITH rollup结果不符合

SQL代码如下：

  SELECT IFNULL(cname,'总平均数') AS "姓名", MAX(CASE cource WHEN "语文" THEN score ELSE 0 END) AS "语文",  MAX(CASE cource WHEN "数学" THEN score ELSE 0 END) AS "数学",  MAX(CASE cource WHEN "物理" THEN score ELSE 0 END) AS "物理",  ROUND(AVG(score),2) AS "总成绩", ROUND(AVG(avg_score),2) AS "平均成绩"     FROM( SELECT     cname ,  IFNULL(cource,'total') cource,  SUM(score) AS score,  ROUND(AVG(score) ,2) AS avg_score FROM tb  GROUP BY `cname`,cource WITH ROLLUP HAVING cname IS NOT NULL )tb2  GROUP BY  tb2.cname WITH ROLLUP;

执行结果不对，总平均数栏目，里面各科比较语文数学的班级平均数不对，如下所示：

mysql>     SELECT IFNULL(cname,'总平均数') AS "姓名",    -> MAX(CASE cource WHEN "语文" THEN score ELSE 0 END) AS "语文",     -> MAX(CASE cource WHEN "数学" THEN score ELSE 0 END) AS "数学",     -> MAX(CASE cource WHEN "物理" THEN score ELSE 0 END) AS "物理",     -> ROUND(AVG(score),2) AS "总成绩",    -> ROUND(AVG(avg_score),2) AS "平均成绩"     ->     FROM(    -> SELECT       -> Display ALL 793 possibilities? (Y OR n)     -> cname ,    -> Display ALL 793 possibilities? (Y OR n)     -> IFNULL(cource,'total') cource,    -> Display ALL 793 possibilities? (Y OR n)     -> SUM(score) AS score,    -> Display ALL 793 possibilities? (Y OR n)     -> ROUND(AVG(score) ,2) AS avg_score    -> FROM tb     -> GROUP BY `cname`,cource WITH ROLLUP HAVING cname IS NOT NULL    -> )tb2     -> GROUP BY  tb2.cname WITH ROLLUP;+--------------+--------+--------+--------+-----------+--------------+| 姓名         | 语文   | 数学   | 物理   | 总成绩    | 平均成绩     |+--------------+--------+--------+--------+-----------+--------------+| 张三         |     74 |     83 |     93 |    125.00 |        83.33 || 李四         |     74 |     84 |     94 |    126.00 |        84.00 || 总平均数     |     74 |     84 |     94 |    125.50 |        83.67 |+--------------+--------+--------+--------+-----------+--------------+3 ROWS IN SET, 1 warning (0.00 sec)mysql>

总结： WITH rollup中对求列的总数是OK的，但是求列的平均数有偏差，这里场景使用不是恰当。

5，使用动态SQL来实现

SQL代码块如下：

/*仅仅班级成员部分*/SET @a=''; SELECT @a:=CONCAT(@a,'SUM(IF(cource=\'',cource,'\'',',score,0)) AS ',cource,',') FROM (SELECT DISTINCT cource FROM tb) A;SET @a=CONCAT(@a,"ROUND(AVG(score) ,2) AS \"平均成绩\"");SET @b=CONCAT('SELECT IFNULL(cname,\'总成绩\'),',LEFT(@a,LENGTH(@a)-1),' ,SUM(score) AS \"总成绩\" FROM tb GROUP BY cname ');/*班级成员总计部分**/SET @a2="";SET @b2=CONCAT('SELECT "all",IFNULL(cname,\'总成绩\'),',LEFT(@a,LENGTH(@a)-1),' ,SUM(score) AS \"总成绩\" FROM tb GROUP BY cname ');SELECT @a2:=CONCAT(@a2,'ROUND(AVG(`',cource,'`),2),') FROM (SELECT DISTINCT cource FROM tb) A;SET @a2=CONCAT(@a2," ROUND(AVG(`平均成绩`),2),ROUND(AVG(`总成绩`),2) ");SET @c=CONCAT("SELECT \"班级平均数\",",LEFT(@a2,LENGTH(@a)-1)," FROM(",@b2,")tb2 GROUP BY tb2.all;");SET @d=CONCAT(@b," UNION ALL ",@c);PREPARE stmt1 FROM @d;EXECUTE stmt1;

查看执行结果如下，已经达到效果：

mysql> /*仅仅班级成员部分*/mysql> SET @a=''; QUERY OK, 0 ROWS affected (0.00 sec)mysql> SELECT @a:=CONCAT(@a,'SUM(IF(cource=\'',cource,'\'',',score,0)) AS ',cource,',') FROM (SELECT DISTINCT cource FROM tb) A;+-----------------------------------------------------------------------------------------------------------------------------------+| @a:=CONCAT(@a,'SUM(IF(cource=\'',cource,'\'',',score,0)) AS ',cource,',')                                                         |+-----------------------------------------------------------------------------------------------------------------------------------+| SUM(IF(cource='语文',score,0)) AS 语文,                                                                                           || SUM(IF(cource='语文',score,0)) AS 语文,SUM(IF(cource='数学',score,0)) AS 数学,                                                    || SUM(IF(cource='语文',score,0)) AS 语文,SUM(IF(cource='数学',score,0)) AS 数学,SUM(IF(cource='物理',score,0)) AS 物理,             |+-----------------------------------------------------------------------------------------------------------------------------------+3 ROWS IN SET (0.00 sec)mysql> SET @a=CONCAT(@a,"ROUND(AVG(score) ,2) AS \"平均成绩\"");QUERY OK, 0 ROWS affected (0.00 sec)mysql> SET @b=CONCAT('SELECT IFNULL(cname,\'总成绩\'),',LEFT(@a,LENGTH(@a)-1),' ,SUM(score) AS \"总成绩\" FROM tb GROUP BY cname ');QUERY OK, 0 ROWS affected (0.00 sec)mysql> mysql> /*班级成员总计部分**/mysql> SET @a2="";QUERY OK, 0 ROWS affected (0.00 sec)mysql> SET @b2=CONCAT('SELECT "all",IFNULL(cname,\'总成绩\'),',LEFT(@a,LENGTH(@a)-1),' ,SUM(score) AS \"总成绩\" FROM tb GROUP BY cname ');QUERY OK, 0 ROWS affected (0.00 sec)mysql> SELECT @a2:=CONCAT(@a2,'ROUND(AVG(`',cource,'`),2),') FROM (SELECT DISTINCT cource FROM tb) A;+-----------------------------------------------------------------------+| @a2:=CONCAT(@a2,'ROUND(AVG(`',cource,'`),2),')                        |+-----------------------------------------------------------------------+| ROUND(AVG(`语文`),2),                                                 || ROUND(AVG(`语文`),2),ROUND(AVG(`数学`),2),                            || ROUND(AVG(`语文`),2),ROUND(AVG(`数学`),2),ROUND(AVG(`物理`),2),       |+-----------------------------------------------------------------------+3 ROWS IN SET (0.00 sec)mysql> SET @a2=CONCAT(@a2," ROUND(AVG(`平均成绩`),2),ROUND(AVG(`总成绩`),2) ");QUERY OK, 0 ROWS affected (0.00 sec)mysql> SET @c=CONCAT("SELECT \"班级平均数\",",LEFT(@a2,LENGTH(@a)-1)," FROM(",@b2,")tb2 GROUP BY tb2.all;");QUERY OK, 0 ROWS affected (0.00 sec)mysql> SET @d=CONCAT(@b," UNION ALL ",@c);QUERY OK, 0 ROWS affected (0.00 sec)mysql> mysql> PREPARE stmt1 FROM @d;QUERY OK, 0 ROWS affected (0.00 sec)Statement preparedmysql> EXECUTE stmt1;+---------------------------+--------+--------+--------+--------------+-----------+| IFNULL(cname,'总成绩')    | 语文   | 数学   | 物理   | 平均成绩     | 总成绩    |+---------------------------+--------+--------+--------+--------------+-----------+| 张三                      |  74.00 |  83.00 |  93.00 |        83.33 |    250.00 || 李四                      |  74.00 |  84.00 |  94.00 |        84.00 |    252.00 || 班级平均数                |  74.00 |  83.50 |  93.50 |        83.67 |    251.00 |+---------------------------+--------+--------+--------+--------------+-----------+3 ROWS IN SET (0.00 sec)mysql>

参考文章地址：http://blog.chinaunix.net/uid-7692530-id-2567582.html

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