PSQLException: 错误: 函数 date_format(timestamp without time zone, unknown) 不存在

-- postgresql兼容MySQL 时间函数date_format
CREATE OR REPLACE FUNCTION date_format(indate anyelement, intext text)
    RETURNS text
    LANGUAGE plpgsql
AS
$function$
BEGIN
    IF upper(inText) = upper('%Y%m%d_%H%i') THEN
        return to_char(inDate, 'YYYYMMDD_HH24MI');
    END IF;
    IF upper(inText) = upper('%Y%m%d%H%i%s') THEN
        return to_char(inDate, 'YYYYMMDDHH24MISS');
    END IF;
    IF upper(inText) = upper('%Y-%m-%d %H') THEN
        return to_char(inDate, 'YYYY-MM-DD HH24');
    END IF;
    IF upper(inText) = upper('%Y-%m-%d') THEN
        return to_char(inDate, 'YYYY-MM-DD');
    END IF;
    IF upper(inText) = upper('%Y-%m') THEN
        return to_char(inDate, 'YYYY-MM');
    end if;
    IF upper(inText) = upper('%m%d') THEN
        return to_char(inDate, 'MMDD');
    END IF;
    return '';
END;
$function$