Mysql - decimals keeps rounding when inserting through php

class ExchangeRates
{
    // have xml and json data
    // this one goes with json, but it works same as xml

    $i = 0;
   foreach ($jsonData as $item) {
       $unit = $item["Unit"];
       $buyRateForeign = $item["buyRateForeign"];
       $meanRate = $item["meanRate"];
       $sellRateForeign = $item["sellRateForeign"];
       
       $database = new Database();
       $sql = "INSERT INTO currency_list (unit, source, buyRateForeign, meanRate, sellRateForeign) VALUES (:unit, :source, :buyRateForeign, :meanRate, :sellRateForeign)";
       $stmt = $database->getConnection->prepare($sql);
       $stmt->bindValue(':unit', $unti);
       // etc...
       $stmt->execute();
       $i++;
    }
}

If I use SELECT query, data will be returned as a string, so for a second I thought that be a reason for not working properly.