MySQL GROUP BY ক্লজে কিভাবে অর্ডার বা সারি বেছে নেবেন?

আসুন প্রথমে একটি টেবিল তৈরি করি -

mysql> create table DemoTable1572
   -> (
   -> StudentId int,
   -> StudentMarks int,
   -> StudentName varchar(20)
   -> );
Query OK, 0 rows affected (0.56 sec)

সন্নিবেশ কমান্ড −

mysql> insert into DemoTable1572 values(1,79,'Sam');
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable1572 values(2,89,'Chris');
Query OK, 1 row affected (0.12 sec)
mysql> insert into DemoTable1572 values(3,98,'David');
Query OK, 1 row affected (0.22 sec)
mysql> insert into DemoTable1572 values(4,79,'Bob');
Query OK, 1 row affected (0.10 sec)

সিলেক্ট স্টেটমেন্ট -

mysql> select * from DemoTable1572;

এটি নিম্নলিখিত আউটপুট −

+-----------+--------------+-------------+
| StudentId | StudentMarks | StudentName |
+-----------+--------------+-------------+
|         1 |           79 |       Sam   |
|         2 |           89 |       Chris |
|         3 |           98 |       David |
|         4 |           79 |       Bob   |
+-----------+--------------+-------------+
4 rows in set (0.00 sec)

MySQL GROUP BY clause-

mysql> select * from DemoTable1572
   -> where StudentId in (select min(StudentId) from DemoTable1572 group by StudentMarks);

এটি নিম্নলিখিত আউটপুট −

+-----------+--------------+-------------+
| StudentId | StudentMarks | StudentName |
+-----------+--------------+-------------+
|         1 |           79 |       Sam   |
|         2 |           89 |       Chris |
|         3 |           98 |       David |
+-----------+--------------+-------------+
3 rows in set (0.10 sec)