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MySQL query to compare and display only the rows with NULL values
For this, you can use IFNULL(). Let us first create a table −
mysql> create table DemoTable ( Value1 int, Value2 int ); Query OK, 0 rows affected (0.75 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable values(10,NULL); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values(20,40); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable values(3,NULL); Query OK, 1 row affected (0.20 sec)
Display all records from the table using select statement −
mysql> select *from DemoTable;
This will produce the following output −
+--------+--------+ | Value1 | Value2 | +--------+--------+ | 10 | NULL | | 20 | 40 | | 3 | NULL | +--------+--------+ 3 rows in set (0.00 sec)
Following is the query to display the rows with NULL values −
mysql> select *from DemoTable where Value1 > IFNULL(Value2,0);
This will produce the following output −
+--------+--------+ | Value1 | Value2 | +--------+--------+ | 10 | NULL | | 3 | NULL | +--------+--------+ 2 rows in set (0.00 sec)
Updated on: 30-Sep-2019
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