Concatenate two columns when one of such column values is null in MySQL

To avoid any issues while running a query, use IFNULL(). Let us first create a table −

mysql> create table DemoTable1793      (      StudentFirstName varchar(20),      StudentLastName varchar(20)      ); Query OK, 0 rows affected (0.00 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable1793 values('John','Smith'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1793 values('Carol',NULL); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1793 values(NULL,'Brown'); Query OK, 1 row affected (0.00 sec)

Display all records from the table using select statement −

mysql> select * from DemoTable1793;

This will produce the following output −

+------------------+-----------------+ | StudentFirstName | StudentLastName | +------------------+-----------------+ | John             |           Smith | | Carol            |            NULL | | NULL             |           Brown | +------------------+-----------------+ 3 rows in set (0.00 sec)

Here is the query to concatenate two columns when one of such column values is null −

mysql> select concat(ifnull(StudentFirstName,''),ifnull(StudentLastName,'')) from DemoTable1793;

This will produce the following output −

+----------------------------------------------------------------+ | concat(ifnull(StudentFirstName,''),ifnull(StudentLastName,'')) | +----------------------------------------------------------------+ | JohnSmith                                                      | | Carol                                                          | | Brown                                                          | +----------------------------------------------------------------+ 3 rows in set (0.00 sec)