DStDev Column in Query

[neo651]

I have a database of prices of products. Each product has a Brand, Category, Type and Subtype. Each product has many prices and I want to calculate the standard deviation of the price of each product. I have a query that lists all products by Brand, Category, Type and Subtype. I need to add a column that calculates the standard deviation of each product (row). I want to make a simple DStDev expression, but I can't figure out a way to do that without the criteria being from a different domain than the domain in the expression, which DStDev can't do. Other ideas or workarounds anyone?

[June7]

Isn't price field in that query?

Why do you need to use the domain aggregate function? Why not StDev in textbox on report?

What criteria?

[neo651]

No, the price field isn't in that query because that query shows only each individual product, but each product has many prices.

I can't do it in a text box because I need to display the standard deviation of multiple products at once in a datasheet view.

Sorry for the ambiguity, I was referring to the criteria of the DStDev statement (<expression>,<domain>, [Criteria])