[Store][Pg] Add support for custom "where" expression

[lyrixx]

Q	A
Bug fix?	no
New feature?	yes
Docs?	no
Issues
License	MIT

I want to be able to filter some record before comparison.
Usage:

$crawlAId = '013e951c-335f-4e2b-9414-9eedbf0f51df';
$crawlBId = '396af6fe-0dfd-47ed-b222-3dbcced3f38e';

$rows = $connection
    ->executeQuery(<<<SQL
        SELECT *
        FROM {$tableName}
        WHERE metadata->>'crawlId' = '{$crawlAId}'
    SQL)
    ->fetchAllAssociative()
;

foreach ($rows as $i => $row) {
    $vector = new Vector(json_decode($row['embedding'], true));
    $documents = $store->query(
        $vector,
        [
            'maxScore' => 0.1,
            'where' => "metadata->>'crawlId' = :crawlId AND id != :currentId",
            'params' => [
                'crawlId' => $crawlBId,
                'currentId' => $row['id'],
            ],
        ],
    );

    if (!$documents) {
        continue;
    }

    $metadata = json_decode($row['metadata'], true, 512, \JSON_THROW_ON_ERROR);
    echo "Current document: {$metadata['url']}\n";
    foreach ($documents as $i => $document) {
        echo "- {$document->metadata['url']} (score: {$document->score})\n";
        if ($i >= 1) {
            break;
        }
    }
    echo "\n";
}

[OskarStark]

We should merge #233 first and rebase this PR then

[OskarStark]

Rebase unlocked :-)

[lyrixx]

Here we go! I have rebased, and added (true) support for param bindings

[OskarStark]

Thank you @lyrixx.