php/mysql count search words and result with keywords limit - php

Question

I have the following PHP search script.
When I search for 1234567, it matches the exact phrase but I want it to match only initial 4 characters i.e. 1234.
Explanation:
I want it to count the initial 4 characters and display the result matching those initial characters. E.g. if someone search for 1234567 then the script should count the initial 4 characters i.e. 1234 and show the results. Similarly if someone search 456789 then the script should count the initial 4 characters i.e. 4567 and show the results.
///explode search term
$search_exploded = explode(" ",$search);
foreach($search_exploded as $search_each)
{
//construct query
$x++;
if ($x==1)
$construct .= "keywords LIKE '%$search_each%'";
else
$construct .= " OR keywords LIKE '%$search_each%'";
}
//echo out construct
$construct = "SELECT * FROM numbers WHERE $construct";
$run = mysql_query($construct);
$foundnum = mysql_num_rows($run);
if ($foundnum==0)
echo "No results found.";
{
echo "$foundnum results found.<p><hr size='1'>";
while ($runrows = mysql_fetch_assoc($run))
{
//get data
$title = $runrows['title'];
$desc = $runrows['description'];
$url = $runrows['url'];
echo "<b>$title</b>
<b>$desc</b>
<a href='$url'>$url</a><p>";

Answer 1

You can replace your foreach with:
foreach($search_exploded as $search_each)
{
$str = mysql_real_escape_string(substr($search_each, 0, 4));
//construct query
$x++;
if ($x==1) $construct .= "keywords LIKE '$str%'";
else $construct .= " OR keywords LIKE '$str%'";
}

Answer 2

To modify your existing code to only use the first 4 words, you just need to change your loop a bit:
Change this-
foreach($search_exploded as $search_each) {
To this -
for($i = 0; $i < min(count($search_exploded), 4); ++$i) {
$search_each = $search_exploded[$i];

Answer 3

Add the following code to the top of your foreach loop:
if(strlen($search_each) > 4) $search_each = substr($search_each, 0, 4);
Like this:
$search_exploded = explode(" ", $search);
foreach($search_exploded as $search_each)
{
if(strlen($search_each) > 4) $search_each = substr($search_each, 0, 4);
// your code
}
This code will search for first 4 characters in every word if that word is longer than 4.