Dynamically create a SQL statment from passed values in PHP - php

Question

I am passing a number of values to a function and then want to create a SQL query to search for these values in a database.
The input for this is drop down boxes which means that the input could be ALL or * which I want to create as a wildcard.
The problem is that you cannot do:
$result = mysql_query("SELECT * FROM table WHERE something1='$something1' AND something2='*'") or die(mysql_error());
I have made a start but cannot figure out the logic loop to make it work. This is what I have so far:
public function search($something1, $something2, $something3, $something4, $something5) {
//create query
$query = "SELECT * FROM users";
if ($something1== null and $something2== null and $something3== null and $something4== null and $something5== null) {
//search all users
break
} else {
//append where
$query = $query . " WHERE ";
if ($something1!= null) {
$query = $query . "something1='$something1'"
}
if ($something2!= null) {
$query = $query . "something2='$something2'"
}
if ($something3!= null) {
$query = $query . "something3='$something3'"
}
if ($something4!= null) {
$query = $query . "something4='$something4'"
}
if ($something5!= null) {
$query = $query . "something5='$something5'"
}
$uuid = uniqid('', true);
$result = mysql_query($query) or die(mysql_error());
}
The problem with this is that it only works in sequence. If someone enters for example something3 first then it wont add the AND in the correct place.
Any help greatly appreciated.

Answer 1

I would do something like this
criteria = null
if ($something1!= null) {
if($criteria != null)
{
$criteria = $criteria . " AND something1='$something1'"
}
else
{
$criteria = $criteria . " something1='$something1'"
}
}
... other criteria
$query = $query . $criteria

Answer 2

try with array.
function search($somethings){
$query = "SELECT * FROM users";
$filters = '';
if(is_array($somethings)){
$i = 0;
foreach($somethings as $key => $value){
$filters .= ($i > 0) ? " AND $key = '$value' " : " $key = '$value'";
$i++;
}
}
$uuid = uniqid('', true);
$query .= $filters;
$result = mysql_query($query) or die(mysql_error());
}
// demo
$som = array(
"something1" => "value1",
"something2" => "value2"
);
search( $som );

Answer 3

Here's an example of dynamically building a WHERE clause. I'm also showing using PDO and query parameters. You should stop using the deprecated mysql API and start using PDO.
public function search($something1, $something2, $something3, $something4, $something5)
{
$terms = array();
$values = array();
if (isset($something1)) {
$terms[] = "something1 = ?";
$values[] = $something1;
}
if (isset($something2)) {
$terms[] = "something2 = ?";
$values[] = $something2;
}
if (isset($something3)) {
$terms[] = "something3 = ?";
$values[] = $something3;
}
if (isset($something4)) {
$terms[] = "something4 = ?";
$values[] = $something4;
}
if (isset($something5)) {
$terms[] = "something5 = ?";
$values[] = $something5;
}
$query = "SELECT * FROM users ";
if ($terms) {
$query .= " WHERE " . join(" AND ", $terms);
}
if (defined('DEBUG') && DEBUG==1) {
print $query . "\n";
print_r($values);
exit();
}
$stmt = $pdo->prepare($query);
if ($stmt === false) { die(print_r($pdo->errorInfo(), true)); }
$status = $stmt->execute($values);
if ($status === false) { die(print_r($stmt->errorInfo(), true)); }
}
I've tested the above and it works. If I pass any non-null value for any of the five function arguments, it creates a WHERE clause for only the terms that are non-null.
Test with:
define('DEBUG', 1);
search('one', 'two', null, null, 'five');
Output of this test is:
SELECT * FROM users WHERE something1 = ? AND something2 = ? AND something5 = ?
Array
(
[0] => one
[1] => two
[2] => five
)
If you need this to be more dynamic, pass an array to the function instead of individual arguments.