通过列值将数组中的MySQL行分组？
要将数组中的行分组，请使用GROUP_CONCAT()以及ORDERBY子句。让我们首先创建一个表-
mysql> create table DemoTable -> ( -> Id int, -> FirstName varchar(20) -> );
使用插入命令在表中插入一些记录-
mysql> insert into DemoTable values(101,'John'); mysql> insert into DemoTable values(102,'Bob'); mysql> insert into DemoTable values(101,'David'); mysql> insert into DemoTable values(101,'Adam'); mysql> insert into DemoTable values(102,'Chris');
使用select语句显示表中的所有记录-
mysql> select *from DemoTable;
这将产生以下输出-
+------+-----------+ | Id | FirstName | +------+-----------+ | 101 | John | | 102 | Bob | | 101 | David | | 101 | Adam | | 102 | Chris | +------+-----------+ 5 rows in set (0.00 sec)
这是按列值将数组中的MySQL行分组的查询-
mysql> select Id,group_concat(FirstName separator ',') from DemoTable -> group by Id -> order by count(Id);
这将产生以下输出-
+------+---------------------------------------+ | Id | group_concat(FirstName separator ',') | +------+---------------------------------------+ | 102 | Bob,Chris | | 101 | John,David,Adam | +------+---------------------------------------+ 2 rows in set (0.00 sec)