BRILLIANT!!!! SELECT `id_fmr`, `fmr_number`, `fmr_system`, `fmr_station`, `created_ts`, GROUP_CONCAT(`seat`) FROM `fmr` JOIN `fmr_has_seat` USING (id_fmr) JOIN `dim_seat` USING (id_dim_seat) WHERE id_fmr = 3 GROUP BY id_fmr;
id_fmr fmr_number fmr_system fmr_station created_ts group_concat(`seat`) ------ ---------- ---------- ----------- ------------------- -------------------- 3 320237274 2333 JFK 2010-09-24 04:35:31 35C,35D,35E > -----Original Message----- > From: Johnny Withers [mailto:joh...@pixelated.net] > Sent: Wednesday, September 29, 2010 1:35 PM > To: Daevid Vincent > Cc: MySQL > Subject: Re: How to get hanging 1:M table rows as single > column in main query? > > GROUP_CONCAT() ? > > And group by id_fmr ? > > JW > > > On Wed, Sep 29, 2010 at 2:38 PM, Daevid Vincent > <dae...@daevid.com> wrote: > > > Given three basic tables. An "fmr" table which has Field Maintenance > > Reports, a Seat table and a "hanging" or "glue" table to > map Seats to FMRs. > > [See below] > > > > How do I get all the Seats to be in a single "row" with the > FMR data? > > > > If I make this kind of query, they come in as separate rows: > > > > SELECT > > `id_fmr`, > > `fmr_number`, > > `fmr_system`, > > `fmr_station`, > > `created_ts`, > > `seat` > > FROM `fmr` > > JOIN `fmr_has_seat` USING (id_fmr) > > JOIN `dim_seat` USING (id_dim_seat) > > WHERE id_fmr = 3; > > > > id_fmr fmr_number fmr_system fmr_station > created_ts seat > > ------ ---------- ---------- ----------- > ------------------- ---- > > 3 320237274 2333 JFK 2010-09-24 04:35:31 35C > > 3 320237274 2333 JFK 2010-09-24 04:35:31 35D > > 3 320237274 2333 JFK 2010-09-24 04:35:31 35E > > > > I want something more like: > > > > id_fmr fmr_number fmr_system fmr_station > created_ts seat > > ------ ---------- ---------- ----------- ------------------- > > ----------- > > 3 320237274 2333 JFK 2010-09-24 04:35:31 > > 35C,35D,35E > > > > > > Now, I'm going to be showing a few thousand FMR rows (and > ideally their > > seats). > > > > What I do now is use PHP to pull the FMR records that match > a certain > > criteria/filter. > > Then I pull in the entire dim_seats as an array and store > it in a session > > since it's not going to change ever. Then I loop over all > the id_fmr that I > > have pulled and look up in the fmr_has_seat table by id_fmr > and implode() > > the seats from the session array. It saves me a few joins > and gets the job > > done, but I keep feeling like there's a better way to do it. > > > > I'm thinking there's some magic with a subselect and concat > or something in > > SQL, but then I wonder if that's any more efficient as > mySQL still has to > > do two SELECTs per FMR row. This feels to me like a common > problem and > > there must be an optimal mySQL way of doing it. Hanging > tables of 1:M > > relationships are used everywhere. > > > > > ============================================================== > ============= > > ================== > > > > CREATE TABLE `fmr` ( > > `id_fmr` int(11) NOT NULL auto_increment, > > `fmr_number` varchar(32) NOT NULL default '', > > `fmr_system` smallint(6) default NULL, > > `fmr_station` varchar(4) NOT NULL default '', > > `created_ts` timestamp NOT NULL default CURRENT_TIMESTAMP, > > PRIMARY KEY (`id_fmr`) > > ) ENGINE=InnoDB > > > > id_fmr fmr_number fmr_system fmr_station created_ts > > ------ ---------- ---------- ----------- ------------------- > > 1 319235F2A 2333 JFK 2010-09-24 04:35:31 > > 2 319235F29 2333 JFK 2010-09-24 04:35:31 > > 3 320237274 2333 JFK 2010-09-24 > 04:35:31 <--- > > 4 32023726D 2333 JFK 2010-09-24 04:35:31 > > 5 32023725A 2333 JFK 2010-09-24 04:35:31 > > 6 32023724F 2333 JFK 2010-09-24 04:35:31 > > 7 320237241 2333 LAX 2010-09-24 04:35:31 > > 8 32023723A 2333 LAX 2010-09-24 04:35:31 > > 9 320237232 2333 JFK 2010-09-24 04:35:31 > > 10 320237230 2333 JFK 2010-09-24 04:35:31 > > .. .. .. .. .. > > > > CREATE TABLE `fmr_has_seat` ( > > `id_fmr` int(11) NOT NULL auto_increment, > > `id_dim_seat` int(10) unsigned NOT NULL, > > PRIMARY KEY (`id_fmr`,`id_dim_seat`), > > KEY `id_dim_seat` (`id_dim_seat`), > > CONSTRAINT `fmr_has_seat_ibfk_1` FOREIGN KEY (`id_fmr`) > REFERENCES `fmr` > > (`id_fmr`) ON DELETE CASCADE ON UPDATE CASCADE, > > CONSTRAINT `fmr_has_seat_ibfk_2` FOREIGN KEY > (`id_dim_seat`) REFERENCES > > `dim_seat` (`id_dim_seat`) ON DELETE CASCADE ON UPDATE CASCADE > > ) ENGINE=InnoDB > > > > id_fmr id_dim_seat > > ------ ----------- > > 3 888 <--- > > 3 889 <--- > > 3 890 <--- > > 4 422 > > 4 423 > > 4 551 > > 4 552 > > 4 553 > > 5 420 > > 5 550 > > 5 628 > > 5 629 > > 5 706 > > 5 707 > > 5 811 > > ... ... > > > > CREATE TABLE `dim_seat` ( > > `id_dim_seat` int(10) unsigned NOT NULL auto_increment, > > `seat` varchar(4) default NULL, > > PRIMARY KEY (`id_dim_seat`), > > KEY `seat` (`seat`) > > ) ENGINE=InnoDB > > > > id_dim_seat seat > > ----------- ------ > > ... ... > > 888 35C <--- > > 889 35D <--- > > 890 35E <--- > > 891 35F > > 892 35G > > ... ... > > > > > > -- > > MySQL General Mailing List > > For list archives: http://lists.mysql.com/mysql > > To unsubscribe: > http://lists.mysql.com/mysql?unsub=joh...@pixelated.net > > > > > > > -- > ----------------------------- > Johnny Withers > 601.209.4985 > joh...@pixelated.net > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org