How to use PDO bindParam for SphinxSearch 3? - pdo

Question

I have recently installed SphinxSearch 3.1.1 on Ubuntu 18 and am currently creating a snippet of code using PHP 7.2. I am having trouble making bindParam work.
Here is my code:
$mytest = "hello";
$query = $conn->prepare("SELECT *, weight() FROM test WHERE MATCH('\"#title :mytest \"/1')");
$query->bindParam(':mytest', $mytest, PDO::PARAM_STR);
$query->execute();
When I try to execute it, result is empty.
However, when I try to directly put $mytest inside the statement, I get the expected result
$query = $conn->prepare("SELECT *, weight() FROM test WHERE MATCH('\"#title". $mytest ."\"/1')");
Does this mean, sphinx does not support bindParam within the MATCH() function? Or am I missing something else here.

Answer 1

Note from http://php.net/manual/en/pdo.prepare.php
Parameter markers can represent a complete data literal only. Neither part of literal, nor keyword, nor identifier, nor whatever arbitrary query part can be bound using parameters.
ie you trying to bind inside a string literal. In the practical sense PHP (or the mysql server) wll add the ' around the value to make the statement.
... In effect would end up with sphinxql query of:
SELECT *, weight() FROM test WHERE MATCH('"#title 'hellow' "/1')
which is clearly wrong!
Instead bind the whole string literal.
$query = $conn->prepare("SELECT *, weight() FROM test WHERE MATCH(:mytest)");
$query->bindParam(':mytest', '"#title '.$mytest.'"/1', PDO::PARAM_STR);
Although that looks like an invalid Sphinx 'extended syntax' query, The #field qualifer, should be outside the quorum,
$query->bindParam(':mytest', '#title "'.$mytest.'"/1', PDO::PARAM_STR);