How to show average of days between two dates?

[#1]

Hi,

I have tables A,B and C in script.

A table have columns

[NO],
[ENTER],
[TO],
[DATE],
[CONSULTANTBY],
[COUNTRY_ID]

B Have Columns

[NO],
[OVERDATE],
[START],
[END],
[LOCATION],
[LABEL]

C have Columns

[ADDNO],
[TO_I],
[WORKER]

there is join between three tables. I need to create a straight / pivot table with below:

Dimension1 : [TO] where TO='Available' and [LABEL]= 'All files completed'
Dimension2 : [WORKER]
YEARMONTH : Year and Month this should be from START and END

Expression : Avg([DATE] - [OVERDATE])  expression should show average days of DATE minus OVERDATE

can any one help me with dimension and expression please

Thanks.

[sunny_talwar]

I think if you can provide a sample, it would be much more easier to help.