Okay, so effectively a vlookup (excel) but in Clay. I haven't tried it, but you could try Clay's Lookup feature. I assume it will give you a column with the match data, and you can extract the account ID into a new column for all the matching rows. It doesn't look like it will fuzzy match (offers "equals" and "contains" operators) so I'd recommend instead of matching of company name, match the company domain but have Clay normalize the domains first.