On Mon, 2009-12-07 at 12:49 +0100, Merlin Morgenstern wrote: > > Ashley Sheridan wrote: > > On Mon, 2009-12-07 at 11:52 +0100, Merlin Morgenstern wrote: > >> Hello everybody, > >> > >> I am having trouble finding a logic for following problem: > >> > >> Should be true if: > >> page = 1 OR page = 3, but it should also be true if page = 2 OR page = 3 > >> > >> The result should never contain 1 AND 2 in the same time. > >> > >> This obviously does not work: > >> (page = 1 OR page = 3) OR (page = 2 OR page = 3) > >> > >> This also does not work: > >> (page = 1 OR page = 3 AND page != 2) OR (page = 2 OR page = 3 AND page != 1) > >> > >> Has somebody an idea how to solve this? > >> > >> Thank you in advance for any help! > >> > >> Merlin > >> > >> > > > > I thought this might work: > > > > (page = 3) OR (page = 1 XOR 2) > > > > But having given it more thought, I'm not so sure. I assume from your > > example that this is MySQL code and not PHP. Having said that, how can > > a field of one row have more than one value? Surely `page` is either > > 1, 2 or 3, not two of them at once. How do you want your results > > pulled? Assuming you have rows containing all three values, how do you > > decide which of the pair of results you want? > > > > Thanks, > > Ash > > http://www.ashleysheridan.co.uk > > > > > > > You have described the problem very well. This is exactly where I can > not find a solution. > > the page number translates to the following: 1= first page 2= following > pages 3= all pages > > This are the options a user has while booking a product on my site. Now > if ther is a new > client that wants to book all pages, I need to query the table to find > out if the spot is available. > The spot would be full if page 1 has more results then 3 , OR all > following pages have more then 3 results. So to find out if "all pages" > option would be available I need to query the db to retrieve all > results, that are (page = 3) OR (page = 1 XOR 2) > > Am I wrong? > I'm pretty confused by your logic, but I think the only way you can achieve what you want is with multiple queries and counts. Thanks, Ash http://www.ashleysheridan.co.uk
