आप इसके लिए COUNT(*) के साथ GROUP BY का उपयोग कर सकते हैं। आइए पहले एक टेबल बनाते हैं:
mysql> create table DemoTable ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentAge int ); Query OK, 0 rows affected (0.59 sec)
इन्सर्ट कमांड का उपयोग करके टेबल में रिकॉर्ड डालें:
mysql> insert into DemoTable(StudentAge) values(16); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable(StudentAge) values(17); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable(StudentAge) values(18); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(StudentAge) values(17); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(StudentAge) values(17); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable(StudentAge) values(17); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable(StudentAge) values(18); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(StudentAge) values(18); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable(StudentAge) values(19); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(StudentAge) values(19); Query OK, 1 row affected (0.07 sec) mysql> insert into DemoTable(StudentAge) values(16); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(StudentAge) values(16); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(StudentAge) values(15); Query OK, 1 row affected (0.16 sec)
सेलेक्ट स्टेटमेंट का उपयोग करके टेबल से सभी रिकॉर्ड प्रदर्शित करें:
mysql> select * from DemoTable;
इससे निम्न आउटपुट प्राप्त होगा:
+-----------+------------+ | StudentId | StudentAge | +-----------+------------+ | 1 | 16 | | 2 | 17 | | 3 | 18 | | 4 | 17 | | 5 | 17 | | 6 | 17 | | 7 | 18 | | 8 | 18 | | 9 | 19 | | 10 | 19 | | 11 | 16 | | 12 | 16 | | 13 | 15 | +-----------+------------+ 13 rows in set (0.00 sec)
फ्रीक्वेंसी गिनने का क्वेरी:
mysql> select StudentAge,count(*) AS `AgeFrequency` from DemoTable group by StudentAge;
इससे निम्न आउटपुट प्राप्त होगा:
+------------+--------------+ | StudentAge | AgeFrequency | +------------+--------------+ | 16 | 3 | | 17 | 4 | | 18 | 3 | | 19 | 2 | | 15 | 1 | +------------+--------------+ 5 rows in set (0.05 sec)
