每天单表入库100万数据，200多张表，每小时对前一小时数据进行处理，建表语句和查询语句如下, 请问下大佬们需要做哪些优化？

create table edgebox4_mtplc_smotorpower
(
    reading_time  timestamp with time zone not null
        constraint edgebox4_mtplc_smotorpower_pkey
            primary key,
    event_time    timestamp with time zone,
    reading_value double precision
);

sql = "select to_char(reading_time, 'YYYY-MM-DD HH24:MI'), avg(reading_value) " \
          " from " + box_id + "_" + variable + \
          " where to_char(reading_time, 'YYYY-MM-DD HH24') = '" + hour + \
          "' group by to_char(reading_time, 'YYYY-MM-DD HH24:MI')" \
          "order by to_char(reading_time, 'YYYY-MM-DD HH24:MI');"