How can I find distance between two sets of genomic position data

I have two sets of data, looking like that:

 chr1 7777777      chr1 55555555
 chr2 8888888      chr1 45555555
                   chr2 88444444
                   chr2 44222222

and i need to find whether there is anything less than 1000 away from chr1 77777777 point, in a second dataset and then repeat it for each point from fist dataset

But i am not sure how to find it since my datasets of different size.

Anyone can help, or suggest the other way to compare genomic position in matlab?

Thank you a lot.