On Tue, August 4, 2015 16:05, Ryan Coleman wrote: > No but there should be. If there's not my task is useless. > > Secondly yes. Unique name on it too. > > -- > Ryan Coleman > Publisher, d3photography.com > ryan.cole...@cwis.biz > m. 651.373.5015 > o. 612.568.2749 > >> On Aug 4, 2015, at 17:33, Wm Mussatto <mussa...@csz.com> wrote: >> >>> On Tue, August 4, 2015 11:19, Ryan Coleman wrote: >>> I have been a MySQL user and supporter for over a decade (since 2001) >>> and >>> I am almost ashamed to admit that I haven’t the faintest idea on how to >>> do >>> joins and unions. >>> >>> I have a specific query I would love to run… >>> >>> I have two tables, one with Unique data (“images”) and one with >>> corresponding paths but many replicated records (“files”). >>> >>> I want to run a query that takes the results from /images/ and also >>> searches /images.file/ as a LIKE statement from /files.path/, sort by >>> /files.filesize/ in descending order returning just the first record >>> (largest file size). There may be up to 750 records from /images/ and >>> thusly could be 3000+ from /files/. >>> >>> How on earth do I do this? >>> >>> — >>> Ryan >> First question, will there always be at least one record in the files >> table for every record in the images table? That controls the kind of >> join you will use. I don't think that a union is a player. Also, is >> there >> a unique record ID in each of the table?
Sorry, been swamped. If you can ignore the cases where there are not any entry in the 'Files' table then a "simple" join will work. Otherwise you would need a LEFT JOIN Assume a structure images.id <- unique record ID images.commonName <- this will be the common reference name in both ... files.id <- unique record ID files.commmonName <- this will be the common reference name in both files.location <-where this record is on the disk/system files.filesize <- numeric field in whatever units you want (say bytes) select images.commonName, files.location, MAX(files.filesize) FROM images, files WHERE images.commonName = files.commonName GROUP BY files.commonName ORDER BY images.commonName Here is my test structure. No doubt someone else can get it optimized. This seems to use a temp table -- -- Table structure for table `files` -- CREATE TABLE `files` ( `ID` int(10) unsigned NOT NULL AUTO_INCREMENT, `CommonName` varchar(255) NOT NULL, `Location` varchar(255) NOT NULL, `filesize` int(11) NOT NULL, PRIMARY KEY (`ID`), KEY `CommonName` (`CommonName`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1; -- -- Dumping data for table `files` -- INSERT INTO `files` (`ID`, `CommonName`, `Location`, `filesize`) VALUES (1, 'Image1', 'FileLoc/1/image1.jpg', 1000), (2, 'Image1', 'FileLoc/2/image1.jpg', 50000), (3, 'Image2', 'FileLoc/1/image2.jpg', 25000), (4, 'Image2', 'FileLoc/2/image2.jpg', 5000); -- -------------------------------------------------------- -- -- Table structure for table `images` -- CREATE TABLE `images` ( `ID` int(10) unsigned NOT NULL AUTO_INCREMENT, `CommonName` varchar(255) NOT NULL, PRIMARY KEY (`ID`), UNIQUE KEY `CommonName` (`CommonName`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8; -- -- Dumping data for table `images` -- INSERT INTO `images` (`ID`, `CommonName`) VALUES (1, 'Image1'), (2, 'Image2'); Hope this helps a bit. ------- William R. Mussatto, Senior Systems Engineer http://www.csz.com Ph. 909-920-9154 ext 101 Direct: 909-962-8547 ______________________________________________________________________ CONFIDENTIALITY NOTICE: This communication, including attachments, is for the exclusive use of the person or entity to which it is addressed and may contain confidential, proprietary and/or privileged information. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this by mistake, please contact the sender immediately. -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql
