This tutorial will show you how to create PHP/MySQL search engine. You can see the working example used in beSeen on http://bewebmaster.com/software/index.php
Here is the list of some PHP functions used:

trim() - Strip whitespace (or other characters) from the beginning and end of a string
explode() - Split a string by string
array_unique() - Removes duplicate values from an array
preg_replace() - Perform a regular expression search and replace
Other functions used include common database access functions like mysql_connect, mysql_num_rows, etc.

Please see code comments for more detailed explanation of the script. If you have questions or suggestions please use the comment box on the bottom of the page.

Open your favorite editor and create search.php file as shown below.


代码:
<?php 

$hostname_logon = "localhost" ;   
$database_logon = "databaseName" ;  
$username_logon = "databaseUser" ;  
$password_logon = "databasePass" ;   
//open database connection
 $connections = mysql_connect($hostname_logon, $username_logon, $password_logon) or die ( "Unabale to connect to the database" );
 //select database
 mysql_select_db($database_logon) or die ( "Unable to select database!" );

//specify how many results to display per page
$limit = 10;

// Get the search variable from URL
  $var = @$_GET['q'] ;
//trim whitespace from the stored variable
  $trimmed = trim($var);  
//separate key-phrases into keywords
  $trimmed_array = explode(" ",$trimmed); 

// check for an empty string and display a message.
if ($trimmed == "") {
  $resultmsg =  "<p>Search Error</p><p>Please enter a search...</p>" ;
  }

// check for a search parameter
if (!isset($var)){
  $resultmsg =  "<p>Search Error</p><p>We don't seem to have a search parameter! </p>" ;
  }
// Build SQL Query for each keyword entered 
foreach ($trimmed_array as $trimm){
      // EDIT HERE and specify your table and field names for the SQL query
     $query = "SELECT * FROM tablename WHERE field1 LIKE \"%$trimm%\" OR field2 LIKE  \"%$trimm%\" OR field3 LIKE \"%$trimm%\" ORDER BY field1   DESC" ; 
     // Execute the query to  get number of rows that contain search kewords
     $numresults=mysql_query ($query);
     $row_num_links_main =mysql_num_rows ($numresults);

     // next determine if 's' has been passed to script, if not use 0.
     // 's' is a variable that gets set as we navigate the search result pages.
     if (empty($s)) {
         $s=0;
     }

      // now let's get results.
      $query .= " LIMIT $s,$limit" ;
      $numresults = mysql_query ($query) or die ( "Couldn't execute query" );
      $row= mysql_fetch_array ($numresults);

      //store record id of every item that contains the keyword in the array we need to do this to avoid display of duplicate search result.
      do{
          $adid_array[] = $row[ 'fieldid' ];
      }while( $row= mysql_fetch_array($numresults));
 } //end foreach

if($row_num_links_main == 0 && $row_set_num == 0){
   $resultmsg = "<p>Search results for:" . $trimmed  ."</p><p>Sorry, your search returned zero results</p>" ;
}
   //delete duplicate record id's from the array. To do this we will use array_unique function
   $tmparr = array_unique($adid_array); 
   $i=0; 
   foreach ($tmparr as $v) { 
       $newarr[$i] = $v; 
       $i++; 
   } 

// now you can display the results returned. But first we will display the search form on the top of the page
?>

<form action="search.php" method="get" name="search">
  <div align="center">
      <input name="q" type="text" value=" <?php echo $q; ?> " size="15"> 
      <input name="search" type="submit" value="Search">
  </div>
</form>

<?php
// display what the person searched for.
 if( isset ($resultmsg)){
  echo $resultmsg;
  exit();
 }else{
  echo "Search results for: " . $var;
 }
 
foreach($newarr as $value){
 // EDIT HERE and specify your table and field names for the SQL query
$query_value = "SELECT * FROM tablename WHERE fieldid = '$value'";
 $num_value=mysql_query ($query_value);
 $row_linkcat= mysql_fetch_array ($num_value);
 $row_num_links= mysql_num_rows ($num_value);

//now let's make the keywods bold. To do that we will use preg_replace function. 
//Replace field
  $titlehigh = preg_replace ( "'($var)'si" , "<b>\\1</b>" , $row_linkcat[ 'field1' ] );
  $linkhigh = preg_replace ( "'($var)'si" , "<b>\\1</b>" , $row_linkcat[ 'field2' ] );
  $linkdesc = preg_replace ( "'($var)'si" , "<b>\\1</b>" , $row_linkcat[ 'field3' ] );

foreach($trimmed_array as $trimm){
    if($trimm != 'b' ){
        $titlehigh = preg_replace( "'($trimm)'si" ,  "<b>\\1</b>" , $titlehigh);
        $linkhigh = preg_replace( "'($trimm)'si" , "<b>\\1</b>" , $linkhigh);
        $linkdesc = preg_replace( "'($trimm)'si" ,  "<b>\\1</b>" , $linkdesc); 
     }
//end highlight

?>
 <p>
<?php echo $titlehigh; ?><br>
<?php echo $linkhigh; ?><br>
<?php echo $linkhigh; ?>
</p>
 
<?php 
}   //end foreach $trimmed_array 
   if($row_num_links_main > $limit){
   // next we need to do the links to other search result pages
      if ($s>=1) { // do not display previous link if 's' is '0'
        $prevs=($s-$limit);
         echo "<div align='left'><a href='$PHP_SELF?s=$prevs&q=$var&catid=$catid'>Previous " .$limit. "</a></div>";
      }
     // check to see if last page
     $slimit =$s+$limit;
       if (!($slimit >= $row_num_links_main) && $row_num_links_main!=1) {
     // not last page so display next link
          $n=$s+$limit;
           echo "<div align='right'><a href='$PHP_SELF?s=$n&q=$var&catid=$catid'>Next " .$limit. "</a></div>";
        }
    }
}  //end foreach $newarr
?>
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