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MySQL query to update only a single field in place of NULL
For this, you can use COALESCE(). Let us first create a table −
mysql> create table DemoTable1805 ( Name1 varchar(20), Name2 varchar(20) ); Query OK, 0 rows affected (0.00 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable1805 values('Chris',NULL);
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1805 values('David','Mike');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1805 values(NULL,'Mike');
Query OK, 1 row affected (0.00 sec)Display all records from the table using select statement −
mysql> select * from DemoTable1805;
This will produce the following output −
+-------+-------+ | Name1 | Name2 | +-------+-------+ | Chris | NULL | | David | Mike | | NULL | Mike | +-------+-------+ 3 rows in set (0.00 sec
Here is the query to update only one field −
mysql> update DemoTable1805 set Name1 = coalesce(Name1,Name2); Query OK, 1 row affected (0.00 sec) Rows matched: 3 Changed: 1 Warnings: 0
Let us check the table records once again −
mysql> select * from DemoTable1805;
This will produce the following output −
+-------+-------+ | Name1 | Name2 | +-------+-------+ | Chris | NULL | | David | Mike | | Mike | Mike | +-------+-------+ 3 rows in set (0.00 sec)
Updated on: 24-Dec-2019
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