Set Analysis greater than Alternate State Selection

[Anonymous]

I have this expression in a chart.

Sum ({<Date={'>=09/01/2017'}>} AMOUNT)

How do I replace the hard coded date of 09/01/2017 with the date selected in an alternate state?

[sergio0592]

Maybe try with :

Sum ({<Date={">=$(=V_date)"}>} AMOUNT)

V_date=Only( {Alternate_State} Date)

[Anonymous]

That worked!

I added it as

=Sum ({<Date={">=$(=Only( {Alternate_State} Date))"}>} AMOUNT)

I'm confused on what the equals sign does before the Only function.  Why is that needed?