Using key word USING, in which the common linking field is specified. : Using « Join « SQL / MySQL

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2. Join
3. Using

Using key word USING, in which the common linking field is specified.

      
mysql>
mysql>
mysql> CREATE TABLE titles (
    ->   titleID int(11),
    ->   title varchar(100),
    ->   subtitle varchar(100),
    ->   edition tinyint(4),
    ->   publID int(11),
    ->   catID int(11),
    ->   langID int(11),
    ->   year int(11),
    ->   isbn varchar(20),
    ->   comment varchar(255),
    ->   ts timestamp,
    ->   authors varchar(255),
    ->   PRIMARY KEY  (titleID)
    -> );
Query OK, 0 rows affected (0.00 sec)

mysql>
mysql>
mysql>
mysql> INSERT INTO titles VALUES (1,'Linux','Installation',5,1,57,2,2000,NULL,NULL,'2005-02-28 13:34:21','Michael'),
    ->                           (2,'Excel',NULL,NULL,2,3,NULL,2000,NULL,NULL,'2005-02-28 13:34:22','David'),
    ->                           (3,'XML',NULL,NULL,1,2,NULL,1997,NULL,NULL,'2005-02-28 13:34:22','Edwards'),
    ->                           (4,'PHP',NULL,NULL,3,6,NULL,2000,NULL,NULL,'2005-02-28 13:34:22','Tom'),
    ->                           (5,'MySQL','',0,3,34,NULL,2000,'','','2005-02-28 13:34:22','Paul'),
    ->                           (6,'Java',NULL,NULL,4,34,NULL,1999,NULL,NULL,'2005-02-28 13:34:22','Tim');
Query OK, 6 rows affected (0.00 sec)
Records: 6  Duplicates: 0  Warnings: 0

mysql>
mysql> CREATE TABLE publishers (
    ->   publID int(11) NOT NULL auto_increment,
    ->   publName varchar(60) collate latin1_german1_ci NOT NULL default '',
    ->   ts timestamp NOT NULL default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP,
    ->   PRIMARY KEY  (publID),
    ->   KEY publName (publName)
    -> ) ENGINE=InnoDB DEFAULT CHARSET=latin1 COLLATE=latin1_german1_ci;
Query OK, 0 rows affected (0.01 sec)

mysql>
mysql>
mysql> INSERT INTO publishers VALUES (1,'A','2004-12-02 18:36:58'),
    ->                                 (2,'Apress','2004-12-02 18:36:58'),
    ->                                 (3,'New Riders','2004-12-02 18:36:58'),
    ->                                 (4,'O\'Reilly & Associates','2004-12-02 18:36:58'),
    ->                                 (5,'Hanser','2004-12-02 18:36:58');
Query OK, 5 rows affected (0.00 sec)
Records: 5  Duplicates: 0  Warnings: 0

However, this variant assumes that the linking field (in this case publID) has the same name in
both tables. That is, of course, not always the case:
mysql>
mysql> SELECT title, publName FROM titles LEFT JOIN publishers USING (publID);
+-------+-----------------------+
| title | publName              |
+-------+-----------------------+
| Linux | A                     |
| Excel | Apress                |
| XML   | A                     |
| PHP   | New Riders            |
| MySQL | New Riders            |
| Java  | O'Reilly & Associates |
+-------+-----------------------+
6 rows in set (0.00 sec)

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

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

   
    
    
    
    
    
  

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