Setting up SQL queries with multiple parameters - php

Question

I need to set up a SQL query with multiple parameters that are being pulled from the URL. So far I can only get it to work with the there is only one item in the URL.
My default query to pull in all the content
$sql = "SELECT ";
$sql .= "* ";
$sql .= "FROM ";
$sql .= "cms_site_content ";
$sql .= "WHERE ";
$sql .= "1";
I then check if anything was passed through the URL and retrieve it.
if (isset($_GET["d"])) {
$d=$_GET["d"];
Inside the if statement, I break the values passed as "d" into separate items
$newD = explode(',',$d);
$countD = count($newD);
foreach($newD as $discipline) {
if ($countD == 1) {
$sql .= " AND";
$sql .= " discipline='".$discipline."'";
}
My problem is getting the SQL to work if there is more than one discipline value. It should read something like this:
SELECT * FROM cms_site_content WHERE 1 AND discipline="value"
however if there's more than one discipline value, it should read:
SELECT * FROM cms_site_content WHERE 1 AND discipline="value OR discipline="value2" OR discipline="value3"
Is there a more efficient way to write this? I can't figure out how to insert the OR into the foreach statement.

Answer 1

Save all discipline values in an array;
$discipline_arr = array();
foreach($newD as $discipline) {
$discipline_arr[] = $discipline;
// by the way, don't forget to escape for sql injection
// mysql_escape_string is the depracated one, u can use that if u have no
// other choice
}
Then in your sql, add them as discipline in ('value1','value2', 'etc ...') condition (that is for strings, for numeric types it would be like discipline in (1,2,3,4, etc)
$sql = " SELECT * FROM cms_site_content WHERE 1 " .
(empty($discipline_arr) ? "" : "and
discipline in ('". implode("','" , $discipline_arr). "') ") ;
Link to escaping
http://tr1.php.net/manual/en/function.mysql-escape-string.php

Answer 2

Assuming the rest of your query is in tact. Simply store all of your discipline values in an array as follows, then feed the $discipline_string to your $sql query:
$discipline_ary = array('option1', 'option2', 'option3');
$discipline_string = "";
for($i=0; $i < count($discipline_ary); $i++){
$discipline_string .= " discipline = '" . $discipline[$i] . "' ";
if($i+1 == count($discipline_ary)){
break;
}else{
$discipline_string .= " OR "
}
}