Hi, all,
This is my first post on the forum, after doing an intro in that area. I'm growing my knowledge of Excel through various projects and hope you might help me with a specific challenge. Please forgive me if I make some mistake in the form of my query.

I have a table containing data relating to various health and fitness statistics and activities (table is in its infancy and unpoplated so no real point in linking it here). I am hoping to develop a formula that allows the following:

In a particular cell of a table, lets say Z1, I want to input a formula that examines column A and
  • identifies all cells in that column that contain a particular date (either a specified date or the current date--either would work);
  • for all rows that have that date in column A, look to other specified columns (let's say D and E); and
  • uses the data in D and E as inputs for a formula, the result of which is finally displayed in Z1. I don't yet know the formula, but let's assume it's a simple product of the two numbers.

For context, the result in cell Z1 with be a calculation of work performed on a specified date, using elements from cells (in our example) in column D and E. The elements may appear in just one row, or multiple rows. In other words, there may be more than one row in Column A that have the same date. In sum, I want cell Z1 to calculate the PRODUCT of cell D and E all rows with the same date in cell A and then to SUM all of those PRODUCTS.

I hope my question is clear and that I have asked it in an appropriate manner. Thanks!