A列30000条数据,B列8000条数据,找出相同两列相同的值,php实现
A列有30000条数据,B列8000条数据,查找出两列相同的值有多少,并且列出明细,数据类型是int,用php语言如何实现?我的思路是把两列转换成数组,然后进行对比,但是需要循环30000*8000次,想想也是蛋疼,如何把30000条数据合理的切割开,然后在进行对比呢?求大神思路
回复内容:
A列有30000条数据,B列8000条数据,查找出两列相同的值有多少,并且列出明细,数据类型是int,用php语言如何实现?我的思路是把两列转换成数组,然后进行对比,但是需要循环30000*8000次,想想也是蛋疼,如何把30000条数据合理的切割开,然后在进行对比呢?求大神思路
mod区间,简单来拿 {1-100} 和 {2,13,24,35} 来说,
可以每10是一个区间,即 0-9, 10-19 ……
那么0-9 只需要和 2进行对比即可,而不需要和13,24,35进行对比
而 0-9 只需要进行一个mod运算 + 2的mod运算 + 0-9 和2的对比
比之前的 0-9 要和 {2,13,24,35} 都要一一对比好的多
SELECT * FROM test WHERE a=b;
补充:
你拿着8000条的那份数据,一条一条在30000里查,也就只需要8000次而已吧。
php数组有计算交集的方法,array_intersect

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