Question

Here is the query that I am working on:

SELECT `unitid`, `name` FROM apartmentunits
WHERE aptid = (
    SELECT `aptid` FROM rentconditionsmap WHERE rentcondid = 1 AND condnum = 1
)

What I am having trouble figuring out is how to write this to add more rentcondition limiters to filter this list down more.

SELECT `aptid` FROM rentconditionsmap WHERE rentcondid = 1 AND condnum = 1

Data:

CREATE TABLE IF NOT EXISTS `rentconditionsmap` (
   `rcid` bigint(10) unsigned NOT NULL AUTO_INCREMENT, 
   `rentcondid` int(3) unsigned NOT NULL, 
   `condnum` tinyint(3) unsigned NOT NULL, 
   `aptid` bigint(10) unsigned DEFAULT NULL, 
   PRIMARY KEY (`rcid`), KEY `aptid` (`aptid`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=18 ;

INSERT INTO `rentconditionsmap` 
  (`rcid`, `rentcondid`, `condnum`, `aptid`) 
VALUES 
  (1, 1, 1, 1), 
  (2, 2, 1, 1), 
  (3, 3, 0, 1), 
  (4, 4, 1, 1), 
  (5, 8, 0, 1);

CREATE TABLE IF NOT EXISTS `apartmentunits` (
  `unitid` bigint(10) NOT NULL AUTO_INCREMENT, 
  `aptid` bigint(10) NOT NULL, 
  `name` varchar(6) NOT NULL, 
  `verified` tinyint(1) NOT NULL DEFAULT '0', 
  `rentcost` int(4) unsigned DEFAULT NULL, 
  `forrent` tinyint(1) NOT NULL DEFAULT '0', 
  `unittypekey` varchar(2) DEFAULT NULL, 
  `sqft` smallint(6) DEFAULT NULL, 
  PRIMARY KEY (`unitid`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=121 ;

INSERT INTO `apartmentunits` 
  (`unitid`, `aptid`, `name`, `verified`, `rentcost`, `forrent`, `unittypekey`, `sqft`) 
VALUES 
  (1, 1, '3', 1, 540, 0, '2B', NULL), 
  (2, 1, '5', 1, NULL, 0, '2B', NULL), 
  (3, 1, '7', 1, NULL, 0, '2B', NULL), 
  (53, 1, '1', 1, NULL, 0, '2B', NULL), 
  (54, 1, '2', 1, NULL, 0, '2B', NULL), 
  (55, 1, '4', 1, 570, 0, '2B', NULL), 
  (56, 1, '6', 1, NULL, 0, '2B', NULL), 
  (57, 1, '8', 1, NULL, 0, '2B', NULL), 
  (58, 1, '9', 1, NULL, 0, '2B', NULL), 
  (59, 1, '10', 1, NULL, 0, '2B', NULL), 
  (60, 1, '11', 1, NULL, 0, '2B', NULL);

Answer 1

As Eric J said as a comment:

Try changing = to IN

SELECT `unitid`, `name` FROM apartmentunits
WHERE `aptid` IN (
    SELECT `aptid` FROM rentconditionsmap WHERE rentcondid = 1 AND condnum = 1
)