Seriously clever formula required...!

Question

Dear all,
I have been trying to figure this out for so long I’ve actually lost the ability to even ask the question, but here goes...
I would like the information in the ‘Expenses input’ sheet (which is where I keep a running total of my business expenses) to be automatically summed (according to the category I assign the transaction) and displayed in the correct area of the ‘Profit & Loss’ sheet.
If I had a working formula, the ‘Profit & Loss’ sheet in this example should look like this:
CELL D20 = £197.50 (which is the sum of all category 'T1' transactions in period 'April 6th - 30th')
CELL D22 = £149.19 (which is the sum of all category 'T3' transactions in period 'April 6th - 30th')
CELL E20 = £197.50 (which the sum of all category 'T1' transactions in period 'May')
It may be worth mentioning that when a paper receipt comes in to me, I assign it a category which is written on it in pen before being filed away, this system cannot change!
In the interest of avoiding confusion, us English folk use the date format DD/MM/YY!
Any help anyone could give would be enormously appreciated. Once I've figured this out I'll be able to add an income sheet as well as a VAT (value added tax) account which will improve my quality of life no end!
Thank you.

Answer 1

Hi James,
You wrote:
"CELL D20 = £197.50 (which is the sum of all category 'T1' transactions in period 'April 6th - 30th')
CELL D22 = £149.19 (which is the sum of all category 'T3' transactions in period 'April 6th - 30th')
CELL E20 = £197.50 (which the sum of all category 'T1' transactions in period 'May')
Essentially, what you are looking for is a SUMIFS statement.
Here are two possibilities, both shown in the example:
The small table on the left is a representation of part of your Expenses table, showing the expenses in your example.
The two tables on the right are representations of the active part of your P&L table, showing category totals for the sample expenses in the Expenses table. The error warning triangles in the lower table are expected, and are explained below. Several rows are hidden to reduce the size of the screen shot. The tables differ only in the formula used.
(Upper example):
D20: =SUMIFS(Expenses :: $E,Expenses :: $A,$A20,Expenses :: $D,">="&D$1,Expenses :: D,"<"&EOMONTH(D$1,0)+1)
(Lower example):
D20: =SUMIFS(Expenses :: $E,Expenses :: $A,$A20,Expenses :: $D,">="&D$1,Expenses :: D,"<"&E$1)
In each case, the fornula is filled down from D20 to the end of the categories, and  filled right to the last column.
As the second formula references the header cell containing the full date at the top of its column AND the cell containing the date in the next column to the right, the lower version of the table will require one column beyond the last one for which sums are being reported
Both formulas reference the Date and Time value in the cell in row 1 of their own column. This MUST be a true Date and Time value, MUST be the first day of the period to be summed in its column, and MAY need to match the format of the Date and Time value used in column D of the Expenses table. (Note that I used April 1 for the first date. This can be changed to April 7 if you want to eliminate any entries prior to that date.)
The category codes in column A must match exactly those used in column A of the Expenses table.
You will need to change "Expenses" in the formula to the actual name of your Expenses table.
Row 1 is a 'working row', necessary to the formulas, but optional to the user's view. It may be hidden.
Row 2 of the P&L table uses a formula to extract the month from the date in row 1, and display the name of that month.
D2: =MONTHNAME(MONTH(D1))
Fill right a needed.
Details on the functions used may be found in the iWork Formulas and Functions User Guide. The guide may be downloaded via the Help menu in Numbers.
Regrds,
Barry