SUM Product with Date Range

[spf2010]

H
<30 2
>30
A B
12/31/2018 29
12/31/2018 5

My current Formula (adding the days between 0-29)
=SUMPRODUCT((B2:B3>0)*(B2:B3<30))

I would like it to search for whatever date is in column A and If it matches then it will use the sum product formula without me having to select the cell Ranges

 

[Col Delane]

Can you please expand your explanation?
What are the values in B?
Which values are you summing - those in B?
How do the dates in A influence the calculation? (i.e. What does "I would like it to search for whatever date is in column A and If it matches..." mean?)