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How to set default value for empty row in MySQL?
To set default value for empty row, use the concept of COALESCE(). Let us first create a table −
mysql> create table DemoTable1863 ( FirstName varchar(20) ); Query OK, 0 rows affected (0.00 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable1863 values('Chris');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1863 values(NULL);
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1863 values('David');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1863 values(NULL);
Query OK, 1 row affected (0.00 sec)Display all records from the table using select statement −
mysql> select * from DemoTable1863;
This will produce the following output −
+-----------+ | FirstName | +-----------+ | Chris | | NULL | | David | | NULL | +-----------+ 4 rows in set (0.00 sec)
Following is the query to set default value for empty row −
mysql> select coalesce(FirstName,'UNKNOWN NAME') from DemoTable1863;
This will produce the following output −
+------------------------------------+ | coalesce(FirstName,'UNKNOWN NAME') | +------------------------------------+ | Chris | | UNKNOWN NAME | | David | | UNKNOWN NAME | +------------------------------------+ 4 rows in set (0.00 sec)
Updated on: 26-Dec-2019
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