GROUP BY and display only non-empty column values in MySQL

Let us first create a table −

mysql> create table DemoTable    -> (    -> Id varchar(100),    -> Message varchar(200)    -> ); Query OK, 0 rows affected (1.17 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable values('1',''); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values('1','Hi'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable values('2','Hello'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('3','Awesome'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values('3','Good Morning'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values('2',NULL); Query OK, 1 row affected (0.15 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable;

Output

+------+--------------+ | Id   | Message      | +------+--------------+ | 1    |         | | 1    | Hi         | | 2    | Hello        | | 3    | Awesome      | | 3    | Good Morning | | 2    | NULL         | +------+--------------+ 6 rows in set (0.00 sec)

Following is the query to group by and select first non-empty columns −

mysql> select Id,min(Message) from DemoTable -> where Message IS NOT NULL and  length(Message) > 0 -> group by Id;

Output

+------+--------------+ | Id   | min(Message) | +------+--------------+ | 1    | Hi         | | 2    | Hello        | | 3    | Awesome      | +------+--------------+ 3 rows in set (0.06 sec)