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)
Published on 24-Dec-2019 10:35:41
