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Old 03-08-2006, 07:56 PM   #1
Azkaban
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Why can you only use fetch_array only once?
Here's some code. Why can't you do this while statement twice?

PHP Code:
$getbooks = $DB_site->query("SELECT books.* FROM bookdb WHERE bookid>1000");
//FIRST WHILE STATEMENT
$comma="";
while ($getbook = $DB_site->fetch_array($getbooks))
{
  $bookids.="$comma $getbook[bookid]";
  $comma=",";
}
//Run some queries with the $bookids on another table.
//SNIP
while ($getbook = $DB_site->fetch_array($getbooks))
{
  //Do some stuff here, 
  //using an array created with the queries run with $bookids
} 

Unfortunately, I ran a test and the second whil statement is blank. Here's the test:

PHP Code:
$comma="";
        while($getbook = $DB_site->fetch_array($getbooks))
        {
            $bookids.=" $comma ".$getbook[bookid];
            $comma=",";
        }
        echo "here's the bookids test part 1: $bookids<br />";
        $comma="";
        while($getbook = $DB_site->fetch_array($getbooks))
        {
            $bookids2.=" $comma ".$getbook[bookid];
            $comma=",";
        }
        echo "here's the bookids test part 2: $bookids2<br />";
        exit;

here's the bookids test part 1: 450858 , 450678 , 450677 , 450676 , 450675 , 450674 , 450673 , 450671 , 450670 , 450614 , 450612 , 450531 , 450529 , 450528 , 450526 , 450525 , 450523 , 450521 , 450476 , 450454
here's the bookids test part 2: 
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Old 09-25-2006, 06:42 AM   #2
doc
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Re: Why can you only use fetch_array only once?
mysql_fetch_array() returns an array that corresponds to the fetched row and moves the internal data pointer ahead and leaves it there. So repeating the process starts after your values and thus returns nothing.

It does seem odd though. Obviously you never need to repeat it - I assume you were just curious. I'd never spotted it in years of using php!
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Old 09-25-2006, 08:33 PM   #3
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Re: Why can you only use fetch_array only once?
I've come across this requirement and found a way to reset the pointer. Can't remember the code offhand but there is a way to do it.
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