When should I use apostrophes around table names

[barwe]

Hi, 

I found this measure (In book "The Definitive Guide to DAX" 2nd edidtion. graf 5-16) :

Sales Pct All Products and Customers = 
VAR CurrentCategorySales = 
    [Sales Amount]
VAR AllProductAndCustomersSales = 
    CALCULATE( 
        [Sales Amount], 
        ALL ( 'Product' ),
        ALL ( Customer )
    )
VAR Ratio =
    DIVIDE ( 
        CurrentCategorySales, 
        AllProductAndCustomersSales
    )
RETURN Ratio

 I don't understand why Product table is around apostrophes and Customer table is not. 

Is it an oversight or is it for a purpose?

[PaulOlding · Accepted solution]

Hi @barwe 

I suspect it's because Product is also the name of a DAX function, so the apostrophe's are to ensure DAX knows you're talking about a table name rather than the function.

There's no difference in the calculation/result depending on if there is or isn't apostrophes.