Quering for Uniques, question

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July 15th, 2003, 02:25 PM

PFerrara

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Quering for Uniques, question

Hey all,

I have a sort of problem. I have a script that searches for airline routes based on departure and destination. The way its set is this: I have 4 steps. The first step shows a search form to search for either depature airport name or code. Then the script does some manipulating and shows the second step, this is where I have some problems. The script searches through the mysql table for all destinations associated with the selected departure, but sometimes there are multiple flights that go to the same place at different times (for example, Chicago to Detroit, there are something like 6 of them), so when the select menu comes up, it has 6 Detroits, 4 New Yorks, etc. How can I query just to pick up uniques? This way the menu will have one detroit and one new york, then at the last step I can show all of the flights that are Chicago to Detroit.

Thanks

July 15th, 2003, 03:07 PM

nicat23

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You could do something like an inline search, search what you already have saved in your combobox for the next item, if it's found then skip to the next item, and search over, otherwise add it to the list..

example pseudocode:

Quote:

1. Gather all of the results and store them in the array $results
2. Count the # of results that came back from the query and store it in the variable $entries
3. create another array and name it $newentries
4. Zero out variable $x and $y to start nested loops
5. Start loop 1 and loop through $results (use your favorite loop and counting method)
6. Start loop2 and loop through $newentries to compare all values in $newentries to the current value in $results to make sure that none exist
6. If the values exist in $newentries then exit loop2 and go back to step 5, incrimenting x to go to the next entry. Otherwise continue to step 7
7. The value does not exist in $newentries, add it and incriment x and go to step 5 and continue until x = $entries

Hope this helps

Last edited by nicat23 : July 15th, 2003 at 03:11 PM.

July 15th, 2003, 03:14 PM

PFerrara

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yep, that helps a lot, thanks!

July 15th, 2003, 03:17 PM

nicat23

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No worries... and I forgot one more thing

Step 8. When you have all of the entries gathered, loop through and add them to a dropdown

Glad to have been able to help

July 15th, 2003, 03:35 PM

PFerrara

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One more question. Instead of doing nested loops and multiple arrays, could I add all of the values from the query to an array, then do an array_unique() on it, and loop through it to add it to the select?

July 15th, 2003, 03:38 PM

nicat23

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possibly but I'm not very sure... Haven't tried using array_unique... let me look into it then I'll post again

July 15th, 2003, 04:29 PM

PFerrara

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Actually, the array_unique does work, if you manipulate it a bit, I found a function on the php.net website that will do the unique strip as well as redo the keys. Here is the function and my final code:

PHP Code:


		
			
function array_unique_key($_array){

        $tmparr = array_unique($_array);

        $i=0;

        foreach ($tmparr as $v) { 

        $newarr[$i] = $v;

        $i++;

        }

        return $newarr;

}

PHP Code:


		
			
while($row = mysql_fetch_array($result)){

               $dc = $row['to_loc'];

               array_push($ds, $dc);

           }

$ds = array_unique_key($ds);

$r = "";

foreach($ds as $dc){

               $dquery = "SELECT name FROM TABLE WHERE FIELD= '$dc'";

               $dresult = mysql_query($dquery) or die("Error: " . mysql_error());

               $dl = mysql_fetch_array($dresult);

               $dn = $dl['name'];

               $r .= "<option value=\"route.php?step=3&o=" . $o . "&d=" . $dc . "\">" . $dn . "</option>\n";

}

That worked fine

Last edited by PFerrara : July 15th, 2003 at 04:31 PM.

July 15th, 2003, 04:32 PM

nicat23

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Sweet

you taught me something new... Thanks!!

July 16th, 2003, 09:59 AM

PFerrara

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Another even easier way to get back uniques is to SELECT DISTINCT in the sql query, instead of just SELECT

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