Возможно, у меня полная разбивка здесь, но не должны ли JOIN ON и JOIN USING давать одинаковые результаты при одинаковых полях?
например,
SELECT * FROM racks r join rack_positions p on (r.rack_id=p.rack_id);//46 rows
SELECT * FROM racks r join rack_positions p using (rack_id);//zero rows
Так почему же вышеупомянутые запросы не дают одинаковый результат?(Бьюсь об заклад, я собираюсь ударить себя за то, что не понял этого.)
CREATE TABLE, заявления
CREATE TABLE `racks` (
`rack_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`watersystem_id` int(10) unsigned NOT NULL,
`pgroup_id` int(10) unsigned DEFAULT NULL,
`rack_name` varchar(20) NOT NULL,
`barcode_id` int(10) unsigned DEFAULT NULL,
`row_max` int(10) unsigned NOT NULL DEFAULT '0',
`spigot_max` int(10) unsigned NOT NULL DEFAULT '0',
`added_by` int(10) unsigned DEFAULT NULL,
`added_on` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
`modded_by` int(10) unsigned DEFAULT NULL,
`modded_on` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00' ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`rack_id`),
UNIQUE KEY `watersystem_id` (`watersystem_id`,`rack_name`) USING BTREE,
UNIQUE KEY `FK_racks_2` (`barcode_id`) USING BTREE,
KEY `pgroup_id` (`pgroup_id`),
CONSTRAINT `FK_racks_2` FOREIGN KEY (`barcode_id`) REFERENCES `barcodes` (`barcode_id`),
CONSTRAINT `racks_ibfk_1` FOREIGN KEY (`watersystem_id`) REFERENCES `watersystems` (`watersystem_id`),
CONSTRAINT `racks_ibfk_2` FOREIGN KEY (`pgroup_id`) REFERENCES `perm_groups` (`pgroup_id`) ON DELETE SET NULL
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=latin1 ROW_FORMAT=DYNAMIC;
CREATE TABLE `rack_positions` (
`pos_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`rack_id` int(10) unsigned NOT NULL,
`row_num` tinyint(3) unsigned NOT NULL,
`spigot_num` tinyint(3) unsigned NOT NULL,
`operating` tinyint(1) DEFAULT '1' COMMENT 'set to false if location cannot be used',
`notes` text COMMENT 'optional note about why a location might be non-operational',
`barcode_id` int(10) unsigned DEFAULT NULL,
`added_by` int(10) unsigned DEFAULT NULL,
`added_on` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
`modded_by` int(10) unsigned DEFAULT NULL,
`modded_on` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00' ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`pos_id`),
UNIQUE KEY `FK_locations_2` (`barcode_id`) USING BTREE,
KEY `rack_id` (`rack_id`),
KEY `FK_rack_positions_3` (`added_by`),
KEY `FK_rack_positions_4` (`modded_by`),
CONSTRAINT `FK_rack_positions_4` FOREIGN KEY (`modded_by`) REFERENCES `users` (`user_id`) ON DELETE SET NULL,
CONSTRAINT `FK_locations_2` FOREIGN KEY (`barcode_id`) REFERENCES `barcodes` (`barcode_id`),
CONSTRAINT `FK_rack_positions_3` FOREIGN KEY (`added_by`) REFERENCES `users` (`user_id`) ON DELETE SET NULL,
CONSTRAINT `rack_positions_ibfk_1` FOREIGN KEY (`rack_id`) REFERENCES `racks` (`rack_id`) ON DELETE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=98 DEFAULT CHARSET=latin1 ROW_FORMAT=DYNAMIC;