MySQL Select Rows where two columns do not have the same value?
You can use != operator from MySQL for this. The syntax is as follows:
SELECT *FROM yourTableName
WHERE yourColumnName1 !=yourColumnName2
OR (yourColumnName1 IS NULL AND yourColumnName2IS NOT NULL)
OR (yourColumnName2 IS NULL AND yourColumnName1 IS NOT NULL);
To understand the above syntax, let us create a table. The query to create a table is as follows:
mysql> create table selectTwoColumns
-> (
-> Id int NOT NULL AUTO_INCREMENT,
-> FirstNumber int,
-> SecondNumber int,
-> PRIMARY KEY(Id)
-> );
Query OK, 0 rows affected (0.87 sec)
Insert some records in the table using insert command. The query is as follows:
mysql> insert into selectTwoColumns(FirstNumber,SecondNumber) values(10,20);
Query OK, 1 row affected (0.29 sec)
mysql> insert into selectTwoColumns(FirstNumber,SecondNumber) values(30,40);
Query OK, 1 row affected (0.16 sec)
mysql> insert into selectTwoColumns(FirstNumber,SecondNumber) values(20,20);
Query OK, 1 row affected (0.15 sec)
mysql> insert into selectTwoColumns(FirstNumber,SecondNumber) values(50,60);
Query OK, 1 row affected (0.18 sec)
mysql> insert into selectTwoColumns(FirstNumber,SecondNumber) values(50,50);
Query OK, 1 row affected (0.17 sec)
mysql> insert into selectTwoColumns(FirstNumber,SecondNumber) values(70,NULL);
Query OK, 1 row affected (0.14 sec)
Display all records from the table using select statement. The query is as follows:
mysql> select *from selectTwoColumns;
The following is the output:
+----+-------------+--------------+
| Id | FirstNumber | SecondNumber |
+----+-------------+--------------+
| 1 | 10 | 20 |
| 2 | 30 | 40 |
| 3 | 20 | 20 |
| 4 | 50 | 60 |
| 5 | 50 | 50 |
| 6 | 70 | NULL |
+----+-------------+--------------+
6 rows in set (0.00 sec)
Here is the query to select rows where two columns do not have same value:
mysql> select *from selectTwoColumns
-> where FirstNumber!=SecondNumber
-> OR (FirstNumber IS NULL AND SecondNumber IS NOT NULL)
-> OR (SecondNumber IS NULL AND FirstNumber IS NOT NULL);
The following is the output:
+----+-------------+--------------+
| Id | FirstNumber | SecondNumber |
+----+-------------+--------------+
| 1 | 10 | 20 |
| 2 | 30 | 40 |
| 4 | 50 | 60 |
| 6 | 70 | NULL |
+----+-------------+--------------+
4 rows in set (0.00 sec)
Published on 25-Feb-2019 09:50:29
