Count duplicate records : COUNT « Aggregate Functions « SQL / MySQL

1. SQL / MySQL
2. Aggregate Functions
3. COUNT

Count duplicate records

        
mysql>
mysql> CREATE   TABLE PENALTIES
    ->         (PAYMENTNO      INTEGER      NOT NULL,
    ->          EmployeeNO       INTEGER      NOT NULL,
    ->          PAYMENT_DATE   DATE         NOT NULL,
    ->          AMOUNT         DECIMAL(7,2) NOT NULL,
    ->          PRIMARY KEY    (PAYMENTNO)          );
Query OK, 0 rows affected (0.00 sec)

mysql>
mysql> INSERT INTO PENALTIES VALUES (1,  6, '1980-12-08',100);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO PENALTIES VALUES (2, 44, '1981-05-05', 75);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO PENALTIES VALUES (3, 27, '1983-09-10',100);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO PENALTIES VALUES (4,104, '1984-12-08', 50);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO PENALTIES VALUES (5, 44, '1980-12-08', 25);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO PENALTIES VALUES (6,  8, '1980-12-08', 25);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO PENALTIES VALUES (7, 44, '1982-12-30', 30);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO PENALTIES VALUES (8, 27, '1984-11-12', 75);
Query OK, 1 row affected (0.00 sec)

mysql>
mysql> SELECT   EmployeeNO
    -> FROM     PENALTIES
    -> WHERE    AMOUNT > 25
    -> GROUP BY EmployeeNO
    -> HAVING   COUNT(*) > 1
    -> ORDER BY EmployeeNO;
+------------+
| EmployeeNO |
+------------+
|         27 |
|         44 |
+------------+
2 rows in set (0.00 sec)

mysql>
mysql> drop table penalties;
Query OK, 0 rows affected (0.00 sec)

mysql>

   
    
    
    
    
    
    
    
  

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