Excel formula find duplicates with multiple criteria - excel-formula

Question

I am trying to create an excel formula that locates duplicate entries for an employee. Records are pulled from two different systems and then the data is dumped into excel. Below is an example of how the records look. If an employee performed the same task on the same day that is a duplicate.
I've tried the index/match, index/match match, but it will only return the first duplicate (if it even works to do that). I have very little experience with arrays and I've been trying to figure those out to no avail - I feel like this should be easier than I'm making it??
Ideally would want it to return "yes/no" or "duplicate" when a duplicate value is found.
Set One
Client Employee Date
Bob Jones Sally Smith 1/1/2018
Jane Smith Tom Jones 2/1/2018
Set Two
Client Date Employee Task
Bob Jones 1/1/2018 Sally Smith 1
Bob Jones 1/1/2018 Sally Smith 2
Jane Smith 2/1/2018 Tom Jones 1
Jane Smith 2/1/2018 Tom Jones 1

Answer 1

I'm going to show an example using formula based conditional formatting. First you need to select more rules in conditional formatting as shown in the picture below.
After that you pick the option to use the formula to determine which cells to format, and use a formula that looks like this, it's a basic COUNTIFS formula that checks whether the records match at least one other record in the table in all columns that you write down.
=COUNTIFS($A$1:$A$10;$A1;$B$1:$B$10;$B1;$C$1:$C$10;$C1)>1
Note that the default format that the Excel offers you is actually a basic format, so you need to make sure to change it so you know whether the formula is working or not.

Answer 2

I might still be misunderstanding what you're trying to do, but if you want the first table to have a count of how many rows in second table have matching Client&Employee&Date to the first table, you could use COUNTIF (or perhaps VLOOKUP), with the aid of a "helper column" in the second table.
The helper column would concatenate Client&Employee&Date from the second row.
Forgive the weird image example... my beta version of Excel 2019 keeps crashing today and I'm not 100% sure this is what you're trying to do. (If it is what you need to do but don't understand the image, comment # me and I will explain further.)