src/DB/SQLAssembler/PgSQLAssembler.php
public function limit($start, $end = false)
    {
        if ($end) {
            $limit = max(1, (int)$end);
            $offset = $limit * (max(1, (int)$start) - 1);

            $this->offset_is_valid = false;
            return "LIMIT {$limit} OFFSET {$offset} ";
        }

        $start = (int)$start;
        return "LIMIT {$start} ";
    }
public function limit($start, $end = false)
    {
        if ($end) {
            $limit = max(1, (int)$end);
            $offset = $limit * (max(1, (int)$start) - 1);

            $this->offset_is_valid = false;
            return "LIMIT {$limit} OFFSET {$offset} ";
        }

        $start = (int)$start;
        return "LIMIT {$start} ";
    }
PgSQL的limit如果有第二个参数, 那么和mysql的limit行为保持一致, 并且offset()不生效

@param int $start
@param bool|int $end
@return string