php - PDO and MySQL Fulltext searches

Question

I'm converting all my sites code from using mysql_* functions to PDO. The PHP documentation on PDO is not clear for my needs. It gives you the functions to use, but does not go into detail to explain them in different scenarios.

Basically, I have a mysql fulltext search:

$sql = "SELECT ... FROM search_table WHERE MATCH(some_field) AGAINST ('{$searchFor}*' IN BOOLEAN MODE)";

The actual statements much longer, but this is what it basically does.

My question is, how would I incorporate this into PDO?

I know you're not meant to use quotes around the place-marker, so do you leave them out in the AGAINST() function? Do I include them? If I leave them out, what happens to the wildcard symbol etc?

$sql = $this->db->prepare("SELECT ... FROM search_table WHERE MATCH(some_field) AGAINST(:searchText IN BOOLEAN MODE");
$sql->bindValue(':searchText', $searchFor . '*');

Answer 1

This is unfortunately a weird exception to the use of query parameters (edit: but apparently not in the most recent point-release of each MySQL branch, see below).

The pattern in AGAINST() must be a constant string, not a query parameter. Unlike other constant strings in SQL queries, you cannot use a query parameter here, simply because of a limitation in MySQL.

To interpolate search patterns into queries safely, use the PDO::quote() function. Note that PDO's quote() function already adds the quote delimiters (unlike mysql_real_escape_string()).

$quoted_search_text = $this->db->quote('+word +word');

$sql = $this->db->prepare("SELECT ... FROM search_table 
    WHERE MATCH(some_field) AGAINST($quoted_search_text IN BOOLEAN MODE");

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Re comment from @YourCommonSense:

You're right, I just tested this on MySQL 5.5.31, 5.1.68, and 5.0.96 (MySQL Sandbox is a wonderful tool), and it seems that these versions do accept query parameters in the AGAINST() clause of a dynamic SQL query.

I still have a recollection of a conflict existing in the past. Maybe it has been corrected in the most recent point-release of each branch. For example, I find these related bugs:

• Using a stored procedure parameter in the AGAINST() clause always returns the same result: http://bugs.mysql.com/bug.php?id=3734
• Crash or strange results with prepared statement, MATCH and FULLTEXT: http://bugs.mysql.com/bug.php?id=14496