Check for NULL or NOT NULL values in a column in MySQL
For this, use IS NOT NULL in MySQL. Let us see the syntax−
select yourColumnName IS NOT NULL from yourTableName;
The above query returns 1 if the column does not have NULL value otherwise 0. Let us first create a −
mysql> create table DemoTable1408
-> (
-> FirstName varchar(30)
-> );
Query OK, 0 rows affected (0.54 sec)
Insert some records in the table using insert −
mysql> insert into DemoTable1408 values('Chris');
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable1408 values('');
Query OK, 1 row affected (0.12 sec)
mysql> insert into DemoTable1408 values(NULL);
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable1408 values('David');
Query OK, 1 row affected (0.10 sec)Display all records from the table using select −
mysql> select * from DemoTable1408;
This will produce the following output −
+-----------+
| FirstName |
+-----------+
| Chris |
| |
| NULL |
| David |
+-----------+
4 rows in set (0.00 sec)
Following is the query to check for NULL or NOT NULL −
mysql> select FirstName IS NOT NULL from DemoTable1408;
This will produce the following output −
+-----------------------+
| FirstName IS NOT NULL |
+-----------------------+
| 1 |
| 1 |
| 0 |
| 1 |
+-----------------------+
4 rows in set (0.00 sec)
Published on 11-Nov-2019 15:35:03
