PHP search to match all if the term is empty - php

Question

I have written a simple search algorithm for my advanced search of my website.
There are several categories that the advanced search helps the user to limit his/her search. %$variable% is the matching that I use. I want the database to return every possible matches if the title is empty...what should be added/removed to/from this code?
if(isset($_POST['type']) && $_POST['type'] != 0)
{
$type = $_POST['type'];
if($wh == true)
{
$statement .= " AND `type` = '$type' ";
}
else
{
$wh = false;
$statement .= " WHERE `type` = '$type' ";
}
}
if(isset($_POST['sex']) && $_POST['sex'] != 0)
{
$sex = $_POST['sex'];
if($wh == true)
{
$statement .= " AND `sex` = '$sex' ";
}
else
{
$wh = false;
$statement .= " WHERE `sex` = '$sex' ";
}
}
if(isset($_POST['start']) && $_POST['start'] != 0)
{
$start = $_POST['start'];
if($wh == true)
{
$statement .= " AND `start` > '$start' ";
}
else
{
$wh = false;
$statement .= " WHERE `start` > '$start' ";
}
}
if($wh==true)
{
$statement .= " $branch_sentence AND( `title` LIKE '%$search_term%' OR `content` LIKE '%$search_term%' OR `keywords` LIKE '%$search_term%') ORDER BY stars DESC ";
}
else
{
$statement .= " WHERE `title` LIKE '%$search_term%' OR `content` LIKE '%$search_term%' OR `keywords` LIKE '%$search_term%' ORDER BY stars DESC ";
}
// echo $statement;
if($transorder = $site_db->query($statement))
{
$i=0;
while($row_obj = $transorder->fetch_object())
{
$item[$i]['id'] = $row_obj->id;
$item[$i]['pic_main'] = $row_obj->pic_main;
$item[$i]['title'] = $row_obj->title;
$item[$i]['province'] = $row_obj->province;
$item[$i]['stars'] = $row_obj->stars;
$i++;
}
}
}
}

Answer 1

What's wrong with:
if (empty($_POST['title']))
{
$statement = "SELECT id, pic_main, title, province, stars FROM "; // Incomplete b/c I don't know your table name from the question.
}
?