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How to collapse rows into a comma-delimited list with a single MySQL Query?
To collapse rows into a comma-delimited list, use GROUP_CONCAT(). Let us first create a table −
mysql> create table DemoTable ( Id int, Name varchar(40) ); Query OK, 0 rows affected (0.52 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable values(100,'Chris Brown'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(101,'Adam Smith'); Query OK, 1 row affected (0.84 sec) mysql> insert into DemoTable values(101,'John Doe'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(100,'David Miller'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values(101,'Carol Taylor'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable values(103,'Bob Taylor'); Query OK, 1 row affected (0.20 sec)
Display all records from the table using select statement −
mysql> select *from DemoTable;
This will produce the following output −
+------+--------------+ | Id | Name | +------+--------------+ | 100 | Chris Brown | | 101 | Adam Smith | | 101 | John Doe | | 100 | David Miller | | 101 | Carol Taylor | | 103 | Bob Taylor | +------+--------------+ 6 rows in set (0.00 sec)
Following is the query to collapse rows into a comma-delimited list −
mysql> select Id,group_concat(Name) from DemoTable group by Id;
This will produce the following output −
+------+----------------------------------+ | Id | group_concat(Name) | +------+----------------------------------+ | 100 | Chris Brown,David Miller | | 101 | Adam Smith,John Doe,Carol Taylor | | 103 | Bob Taylor | +------+----------------------------------+ 3 rows in set (0.00 sec)
Updated on: 10-Oct-2019
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