duplicates

I'm sure it has been asked and answered, but I missed it.

How do I find duplicates, based upon one column (name, in this case).

Before I found ZOHO, I had my data in several different services, and when they proved unacceptible, had to move it. Each time I moved it, errors such as duplicates crept in.

My best day in a long time was to find ZOHO. THANKS.

Jim West