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MySQL query to set values for NULL occurrence
Find NULL values using the IS NULL and update the new values using MySQL UPDATE and SET −
update yourTableName set yourColumnName=yourValue where yourColumnName IS NULL;
Let us first create a table −
mysql> create table DemoTable768 ( Clientid int NOT NULL AUTO_INCREMENT PRIMARY KEY, ClientName varchar(100), ClientAge int ); Query OK, 0 rows affected (0.47 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable768(ClientName,ClientAge) values('John',23);
Query OK, 1 row affected (0.21 sec)
mysql> insert into DemoTable768(ClientName,ClientAge) values(NULL,26);
Query OK, 1 row affected (0.11 sec)
mysql> insert into DemoTable768(ClientName,ClientAge) values('Carol',28);
Query OK, 1 row affected (0.53 sec)
mysql> insert into DemoTable768(ClientName,ClientAge) values(NULL,24);
Query OK, 1 row affected (0.16 sec)Display all records from the table using select statement −
mysql> select *from DemoTable768;
This will produce the following output -
+----------+------------+-----------+ | Clientid | ClientName | ClientAge | +----------+------------+-----------+ | 1 | John | 23 | | 2 | NULL | 26 | | 3 | Carol | 28 | | 4 | NULL | 24 | +----------+------------+-----------+ 4 rows in set (0.00 sec)
Following is the query to set values for NULL occurrence −
mysql> update DemoTable768 set ClientName='Chris' where ClientName IS NULL; Query OK, 2 rows affected (0.41 sec) Rows matched: 2 Changed: 2 Warnings: 0
Let us check the description of the view −
mysql> select *from DemoTable768;
This will produce the following output -
+----------+------------+-----------+ | Clientid | ClientName | ClientAge | +----------+------------+-----------+ | 1 | John | 23 | | 2 | Chris | 26 | | 3 | Carol | 28 | | 4 | Chris | 24 | +----------+------------+-----------+ 4 rows in set (0.00 sec)
Updated on: 03-Sep-2019
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