Using table alias to qualify column name : Simple JOIN « Join « SQL / MySQL






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  2. Join
  3. Simple JOIN

Using table alias to qualify column name

        
mysql>
mysql>
mysql>
mysql> CREATE   TABLE TEAMS
    ->         (TEAMNO         INTEGER      NOT NULL,
    ->          EmployeeNO       INTEGER      NOT NULL,
    ->          DIVISION       CHAR(6)      NOT NULL,
    ->          PRIMARY KEY    (TEAMNO)             );
Query OK, 0 rows affected (0.00 sec)

mysql>
mysql>
mysql> INSERT INTO TEAMS VALUES (1,  6, 'first');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO TEAMS VALUES (2, 27, 'second');
Query OK, 1 row affected (0.00 sec)

mysql>
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   T.EmployeeNO
    -> FROM     TEAMS AS T, PENALTIES AS PEN
    -> WHERE    T.EmployeeNO = PEN.EmployeeNO;
+------------+
| EmployeeNO |
+------------+
|          6 |
|         27 |
|         27 |
+------------+
3 rows in set (0.00 sec)

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

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

mysql>








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