Infrastructure/Database/Queries/QueryBuilder.php
public function null_eq(string $name, $arg)
    {
        if ($arg === null) {
            $this->sql .= "$name is null";
        }
        else {
            $this->args[] = $arg;
            $argNum = count($this->args);
            $this->sql .= "$name = \$$argNum";
        }
        return $this;
    }
public function null_eq(string $name, $arg)
    {
        if ($arg === null) {
            $this->sql .= "$name is null";
        }
        else {
            $this->args[] = $arg;
            $argNum = count($this->args);
            $this->sql .= "$name = \$$argNum";
        }
        return $this;
    }
handle null argument for correct sql
@param string $name
@param $arg
@return $this