sum occurences meeting criteria by ID, then count how many

I closed the duplicate and kept this one, which was started earlier. If you need to update your data you can simply edit your post.

http://www.excelforum.com/showthread...=1#post4439520

This solution uses two formulas. The first is an array entered formula* and makes a unique list of ID's as follows:

Formula:

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The second will identify the frequency of visits as follows:

Formula:

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Attached is a spread sheet that demonstrates how the formulas work. *Array entered formula are confirmed by pressing CTRL+SHIFT+ENTER to activate the array, not just ENTER. You will know the array is active when you see curly braces { } appear around your formula. If you do not CTRL+SHIFT+ENTER you will get an error or a clearly incorrect answer.
Let me know if you have any questions.

Another way.

With a helper cell in D1 (used in lieu of IFERROR) array entered.

Formula:

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If you aren’t familiar with array-entered formulas array enter means the formula must be committed from edit mode by simultaneously pressing and holding down Ctrl and Shift while hitting Enter.

Then in D3 filled down until you get blanks. Does not have to be array entered. This returns unique IDs.

Formula:

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In E3 non-array entered. This returns the sum of each ID < = 90.

Formula:

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In F3 non-array entered. Returns the categories.

Formula:

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You're Welcome and thank you for the feedback. Please take a moment to mark the thread 'Solved' using the thread tools link above your first post. I hope that you have a blessed day.