Re: Select from multiple tables
Kranthi Krishna <[email protected]>
| Newsgroups | gmane.comp.php.database |
|---|---|
| Message-ID | <CAJAheL4sPtaJnkOoEKPSQVyP0DM-7HXRX4-y19aHSZR3ntFd3A@mail.gmail.com> |
Hi, The examples I saw were regarding cartesian join not inner join. I will read about inner joins. Also, the example i mentioned seems to be a mistake. Both school and type will not be similar at the same time Kranthi. http://goo.gl/e6t3 On 1 March 2012 09:26, Kranthi Krishna <[email protected]> wrote: > Hi, > > Thanks for the input. I have seen some tutorials on joins, they all > suggest that MySql returns multiple rows > > For example > -------------------------- > School | Board 1 > -------------------------- > School | Board 1 > ------------------------- > > Now if I have another one-to-many relation > > ----------------------------------- > School | Board 1 | Type 1 > ----------------------------------- > School | Board 1 | Type 2 > ----------------------------------- > School | Board 2 | Type 1 > ----------------------------------- > School | Board 2 | Type 2 > ------------------------------------ > > Using UNIQUE or something similar (like php.net/array_search ) causes > problems when Type 1 = Type 2 etc. > > Kranthi. > http://goo.gl/e6t3 > > > > On 29 February 2012 19:43, Michael Stowe <[email protected]> wrote: >> Select table1.item1, table2.item1 from table1 inner join table2 on table1.key = table2.foreignKey Where... >> >> You can also utilize left and right join to get data if there isn't a direct match (ie customer may not have ordered anything so you want to do a left join on orders as there may not be any order data but you still want to get the customer info). >> >> Hope that helps, >> Mike >> >> >> >> Sent from my iPhone >> >> On Feb 29, 2012, at 8:01 AM, Kranthi Krishna <[email protected]> wrote: >> >>> Hi all, >>> >>> Say I have an object like >>> >>> array >>> schoolName => string >>> board => array >>> string >>> string >>> >>> I generally create two MySql tables >>> >>> schools: id PRIMARY KEY, SchoolName >>> boards: id FOREGIN KEY refers Table A(id), board >>> >>> and then do two selects. The problem is that, the number of selects >>> increase as the number of one-to-many relationships increase. >>> >>> Is there a better way to do this ? I have to extend an existing code >>> so I cannot use any libraries like doctrine >>> >>> Kranthi. >>> http://goo.gl/e6t3 >>> >>> -- >>> PHP Database Mailing List (http://www.php.net/) >>> To unsubscribe, visit: http://www.php.net/unsub.php >>> -- PHP Database Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php