Find A Value On Specific Date – In A Date Range

[elzial4x]

I have different date range (i.e. date of arrival, date of departure), and in this interval I have concrete numeric value (i.e. 20 rooms).
If I have different groups, that need in the +/- same date some availability - how can I sum on a specific day how many units are “used”/booked ?

Example:

1. ARR.: 03/20, DEPART.: 03/25, UNITS: 35
2. ARR.: 03/19, DEPART.: 03/24, UNITS: 27
3. ARR.: 03/22, DEPART.: 03/26, UNITS: 19

If I want to SUM how many units are used on – for example – 03/23, which function/macro/whatever do I need?

Please – help.

Tnx, Dean

[arthurbr]

How is your data organized?
Could you post a sample?

[elzial4x]

Just date of arrival, date of departure, # units (+other "descriptive" data)
See .pdf