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Group MySQL rows in an array by column value?
To group rows in an array, use GROUP_CONCAT() along with the ORDER BY clause. Let us first create a table −
mysql> create table DemoTable -> ( -> Id int, -> FirstName varchar(20) -> ); Query OK, 0 rows affected (0.78 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable values(101,'John'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(102,'Bob'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(101,'David'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values(101,'Adam'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values(102,'Chris'); Query OK, 1 row affected (0.15 sec)
Display all records from the table using select statement −
mysql> select *from DemoTable;
This will produce the following output −
+------+-----------+ | Id | FirstName | +------+-----------+ | 101 | John | | 102 | Bob | | 101 | David | | 101 | Adam | | 102 | Chris | +------+-----------+ 5 rows in set (0.00 sec)
Here is the query to group MySQL rows in an array by column value −
mysql> select Id,group_concat(FirstName separator ',') from DemoTable -> group by Id -> order by count(Id);
This will produce the following output −
+------+---------------------------------------+ | Id | group_concat(FirstName separator ',') | +------+---------------------------------------+ | 102 | Bob,Chris | | 101 | John,David,Adam | +------+---------------------------------------+ 2 rows in set (0.00 sec)
Updated on: 11-Dec-2019
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