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Select different fields in MySQL even if a field is set to null?
For this, you can use COALESCE(). Let us first create a table −
mysql> create table DemoTable1336 -> ( -> FirstName varchar(20) -> , -> SecondName varchar(20) -> ); Query OK, 0 rows affected (0.64 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable1336 values('John',NULL);
Query OK, 1 row affected (0.21 sec)
mysql> insert into DemoTable1336 values(NULL,'Chris');
Query OK, 1 row affected (0.17 sec)
mysql> insert into DemoTable1336 values('David','Mike');
Query OK, 1 row affected (0.18 sec)Display all records from the table using select statement −
mysql> select * from DemoTable1336;
This will produce the following output −
+-----------+------------+ | FirstName | SecondName | +-----------+------------+ | John | NULL | | NULL | Chris | | David | Mike | +-----------+------------+ 3 rows in set (0.00 sec)
Following is the query to select different fields in MySQL even if a field is set to null −
mysql> select coalesce(FirstName,SecondName) as AlternateName from DemoTable1336;
This will produce the following output −
+---------------+ | AlternateName | +---------------+ | John | | Chris | | David | +---------------+ 3 rows in set (0.00 sec)
Updated on: 05-Nov-2019
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