The Excel Dproduct function calculates the product of a field (column) in a database for selected records, that satisfy userspecified criteria.
The syntax of the function is :
where the arguments are shown in the table below:
database    A range of cells containing the database. The top row of the database should specify the field names.  
field   
The field (column) within the database, that you want to calculate the product of.
This can either be a field number, or can be the field name (ie. the header in the top row of the database) encased in quotes (eg. "Date", "Type", etc) 

criteria   
A range of cells that contain the criteria, to specify which records should be included in the calculation.
The range can include one or more criteria, which are presented as a field name in one cell and the condition for that field in the cell below. eg.

Wildcards
You can also use the following wildcards in textrelated criteria:
?  matches any single character
*  matches any sequence of characters
if you do actually want to find the ? or * character, type the ~ symbol before this character in your search.
eg. the condition "A*e" will match all cells containing a text string beginning with "A" and ending in "e".The criteria supplied beneath each field heading can be either:
  a numeric value (including an integer, decimal, date, time, or logical value) (eg. 10, 01/01/2011, FALSE)  
or  
  a text string (eg. "Text", "Monday")  
or  
  an expression (eg. ">12", "<>0") 
Note that the Excel database functions are not case sensitive. So, for example, the criteria ="Tuesday" will be satisfied by cells containing the text "Tuesday" or "tuesday".
A  B  C  D  

1  Name  Date  Test  Score 
2  Gary  01Jan2011  Test1  4 
3  Gary  01Jan2011  Test2  4 
4  Gary  01Jan2011  Test3  3 
5  Gary  05Jan2011  Test1  3 
6  Gary  05Jan2011  Test2  4 
7  Gary  05Jan2011  Test3  3 
8  Kev  02Jan2011  Test1  2 
9  Kev  02Jan2011  Test2  3 
10  Kev  02Jan2011  Test3  5 
11  Kev  05Jan2011  Test1  3 
12  Kev  05Jan2011  Test2  2 
13  Kev  05Jan2011  Test3  5 
The following examples are based on the above simple database on the right, which stores the ratings, across three tests, taken by two men on different dates.
In the example below, the Dproduct function is used to calculate the product of Gary's scores on all three tests on 05Jan2010. The criteria are specified in cells F1  G2 and the Dproduct formula is shown in cell F3.
F  G  

1  Name  Date 
2  Gary  05Jan2011 
3  =DPRODUCT( A1:D13, "Score", F1:G2 ) 
The above Dproduct function calculates the product of the scores in cells D5, D6 & D7, and therefore returns the value 36.
In the example below, the Dproduct function is used to calculate the product of all scores for Test1 on dates prior to 05Jan2011.
F  G  

1  Test  Date 
2  Test1  < 05Jan2011 
3  =DPRODUCT( A1:D17, "Score", F1:G2 ) 
The above Dproduct function calculates the product of the scores in cells D2 and D8 and so returns the value 8.
Note that, in the above two examples, instead of typing in "Score" for the field argument, we could have simply used the number 4 (to denote the 4th column of the database).
Further examples of the Excel Dproduct function can be found on the Microsoft Office website.