Since we cannot use MINUS query in MySQL, we will use LEFT JOIN to simulate the MINUS query. It can be understood with the help of the following example:
Example
In this example, we are two tables namely Student_detail and Student_info having the following data −
mysql> Select * from Student_detail; +-----------+---------+------------+------------+ | studentid | Name | Address | Subject | +-----------+---------+------------+------------+ | 101 | YashPal | Amritsar | History | | 105 | Gaurav | Chandigarh | Literature | | 130 | Ram | Jhansi | Computers | | 132 | Shyam | Chandigarh | Economics | | 133 | Mohan | Delhi | Computers | | 150 | Rajesh | Jaipur | Yoga | | 160 | Pradeep | Kochi | Hindi | +-----------+---------+------------+------------+ 7 rows in set (0.00 sec) mysql> Select * from Student_info; +-----------+-----------+------------+-------------+ | studentid | Name | Address | Subject | +-----------+-----------+------------+-------------+ | 101 | YashPal | Amritsar | History | | 105 | Gaurav | Chandigarh | Literature | | 130 | Ram | Jhansi | Computers | | 132 | Shyam | Chandigarh | Economics | | 133 | Mohan | Delhi | Computers | | 165 | Abhimanyu | Calcutta | Electronics | +-----------+-----------+------------+-------------+ 6 rows in set (0.00 sec)
Now, the following query using LEFT JOIN will simulate MINUS to return the ‘studentid’ values in student_info but not in Student_detail table.
mysql> SELECT studentid from student_info LEFT JOIN Student_detail USING(studentid) WHERE student_detail.studentid IS NULL; +-----------+ | studentid | +-----------+ | 165 | +-----------+ 1 row in set (0.07 sec)
Now, the following query will give us the opposite result of above query i.e. it will return the ‘studentid’ values in student_detail but not in Student_info table.
mysql> SELECT studentid from student_detail LEFT JOIN Student_info USING(studentid) WHERE student_info.studentid IS NULL; +-----------+ | studentid | +-----------+ | 150 | | 160 | +-----------+ 2 rows in set (0.00 sec)