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Aug 27, 2017 Replied to a topic by gouwudang › 酷工作 › [南京] 求 Python 数据工程师（全职到手薪资： 8-16K*13 个月，实习到手： 200-400￥/天） |
薪资明确的招聘贴好评！
Jun 30, 2017 Replied to a topic by dingzi › 推广 › 115 网盘会员特价 限时返现优惠 少年要不要上车呢？ |
订单尾号 4642
Nov 24, 2016 Replied to a topic by Jolly23 › 问与答 › 关于 SQL 语句查询“短信中每个人有多少个联系人”的写法，求教 |
select send_id, count(1)
from (select distinct send_id, receive_id from table)
group by send_id;
搜到一篇优化文章，可能有用
https://www.oschina.net/translate/use-subqueries-to-count-distinct-50x-faster
from (select distinct send_id, receive_id from table)
group by send_id;
搜到一篇优化文章，可能有用
https://www.oschina.net/translate/use-subqueries-to-count-distinct-50x-faster
May 11, 2016 Replied to a topic by benson458 › 问与答 › oracle 如何”更快的“返回指定行数之间的查询结果？？？ |
select *
from (select rownum rn, a.*
from (select * from XXX where YYY order by ZZZ) a
where rownum < 50)
where rn > 30;
from (select rownum rn, a.*
from (select * from XXX where YYY order by ZZZ) a
where rownum < 50)
where rn > 30;
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