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[2001-02-27 10:52 UTC] ssegarra at mitre dot org
<?
$db = mysql_connect("localhost", "web") || print "error connecting ".mysql_error()." ".mysql_errno();
mysql_select_db("surveys");
$result = mysql_query("select * from attract") || print "error querying ".mysql_error()." ".mysql_errno();
$i = 0;
while ($row = mysql_fetch_array($result)){ // && ($i++ < 5)){
echo $row[0]." ".$row[1]."<br>";
}
?>
this script will repeatedly give me invalid MySQL Link Resource Warnings, but by changing the "||" to "or" it will work fine.
Thanks
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Last updated: Sat Nov 01 23:00:01 2025 UTC |
This isn't a bug; it's a result of the differing precedence for || and or (which are otherwise identical, btw). Try this: $db = mysql_connect("localhost", "root") || print "error connecting"; echo $db; The output should be '1'. The reason is that || has higher precedence than =, so PHP sees the above statement as: $db = (mysql_connect("localhost", "root") || print "error connecting"); ...which means that $db is assigned the value of the expression in parens, which in this case will always evaluate to 1, which is not a valid MySQL resource. Next try this: ($db = mysql_connect("localhost", "web")) || print "error connecting "; echo $db; The output should be 'Resource id #1', since the precedence has now been forced. The other way to force precedence is to use the lower-precedence 'or', as you mentioned. The operator precedence table can be found in the manual at: http://www.php.net/manual/en/language.operators.precedence.php Hope this helps, Torben