使用UNION实现mysql 行列变换（一）
作者：互联网
表格1：表名：score
+------+---------+---------+------+-------+ | name | chinese | english | math | total | +------+---------+---------+------+-------+ | Tom | 90 | 80 | 100 | 270 | +------+---------+---------+------+-------+
表格2：
+---------+-------+ | subject | value | +---------+-------+ | 语文 | 90 | | 数学 | 100 | | 英语 | 80 | | 总分 | 270 | +---------+-------+
要把表格1 变成 表格2
方法1：
第一步：
select ''subject,0 value from dual;
结果为：
+---------+-------+ | subject | value | +---------+-------+ | | 0 | +---------+-------+
第二步：
select '语文' subject, (select chinese from score) value;
结果为：
+---------+-------+ | subject | value | +---------+-------+ | 语文 | 90 | +---------+-------+
使用union将结果组合
select '语文' subject, (select chinese from score) value union select '数学' subject, (select math from score) value union select '英语' subject,(select english from score) value union select '总分' subject,(select total from score) value;
+---------+-------+ | subject | value | +---------+-------+ | 语文 | 90 | | 数学 | 100 | | 英语 | 80 | | 总分 | 270 | +---------+-------+
标签：UNION,+---------+-------+,value,行列,score,mysql,union,select,subject 来源： https://www.cnblogs.com/conpi/p/16670233.html