system/Database/BaseBuilder.php
public function countAll(bool $reset = true, bool $test = false)
	{
		$table = $this->QBFrom[0];

		$sql = $this->countString . $this->db->escapeIdentifiers('numrows') . ' FROM ' .
				$this->db->protectIdentifiers($table, true, null, false);

		if ($test)
		{
			return $sql;
		}

		$query = $this->db->query($sql, null, false);
		if (empty($query->getResult()))
		{
			return 0;
		}

		$query = $query->getRow();

		if ($reset === true)
		{
			$this->resetSelect();
		}

		return (int) $query->numrows;
	}
public function countAll(bool $reset = true, bool $test = false)
	{
		$table = $this->QBFrom[0];

		$sql = $this->countString . $this->db->escapeIdentifiers('numrows') . ' FROM ' .
				$this->db->protectIdentifiers($table, true, null, false);

		if ($test)
		{
			return $sql;
		}

		$query = $this->db->query($sql, null, false);
		if (empty($query->getResult()))
		{
			return 0;
		}

		$query = $query->getRow();

		if ($reset === true)
		{
			$this->resetSelect();
		}

		return (int) $query->numrows;
	}
"Count All" query

Generates a platform-specific query string that counts all records in
the specified database

@param boolean $reset Are we want to clear query builder values?
@param boolean $test  Are we running automated tests?

@return integer|string when $test = true