To insert a NULL value, you can use UPDATE command. Following is the syntax −
UPDATE yourTableName SET yourColumnName=NULL;
Let us first create a table −
mysql> create table insertNullValue -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> ClientName varchar(100), -> ClientCountryName varchar(20) -> ); Query OK, 0 rows affected (0.54 sec)
Following is the query to insert some records in the table using insert command −
mysql> insert into insertNullValue(ClientName,ClientCountryName) values('Larry','US'); Query OK, 1 row affected (0.19 sec) mysql> insert into insertNullValue(ClientName,ClientCountryName) values('David','AUS'); Query OK, 1 row affected (0.09 sec) mysql> insert into insertNullValue(ClientName,ClientCountryName) values('Bob','UK'); Query OK, 1 row affected (0.17 sec)
Following is the query to display all records from the table using select statement −
mysql> select * from insertNullValue;
This will produce the following output −
+----+------------+-------------------+ | Id | ClientName | ClientCountryName | +----+------------+-------------------+ | 1 | Larry | US | | 2 | David | AUS | | 3 | Bob | UK | +----+------------+-------------------+ 3 rows in set (0.00 sec)
Following is the query to insert NULL value for a column −
mysql> update insertNullValue set ClientCountryName=NULL; Query OK, 3 rows affected (0.19 sec) Rows matched: 3 Changed: 3 Warnings: 0
Let us check the NULL value is inserted for the column ‘ClientCountryName’ or not. Following is the query −
mysql> select * from insertNullValue;
This will produce the following output displaying the NULL values −
+----+------------+-------------------+ | Id | ClientName | ClientCountryName | +----+------------+-------------------+ | 1 | Larry | NULL | | 2 | David | NULL | | 3 | Bob | NULL | +----+------------+-------------------+ 3 rows in set (0.00 sec)