=ARRAYFORMULA(SUM((A2:A12="a")*(B2:D12>0))

Sometimes it's easier to just work with Booleans like they're arrays of 0s and 1s.

Use a combination of the ARRAYFORMULA, SUM and arithmetic operations

Use the approach provided in barry houdini's answer. To count all of the clicks by a 26 year old:

=ARRAYFORMULA(sum((A:A=26) * (C:C="true")))

There are 3 parts to this operation.

• The ARRAYFORMULA takes care of looping over the specified range
• The SUM manages counting all of the true results

Essentially, true is being converted to 1 and false is being converted to 0. Boolean logic is done by using arithmetic operations.

An AND operation uses multiplication:

• (1 * 1) = 1 - (True && True) = True
• (1 * 0) = 0 - (True && False) = False
• (0 * 0) = 0 - (False && False) = False

An OR operation uses a combination of the *SIGN function and addition:

• sign(1 + 1) = 1 - (True || True) = True
• sign(1 + 0) = 1 - (True || False) = True
• sign(0 + 0) = 0 - (False || False) = False

Note: The sign function is necessary because of the way boolean addition works differently than arithmetic addition. Basically in boolean addition 1 + 1 = 1, in arithmetic addition 1 + 1 = 2. Obviously, arithmetic addition will mess up the count so you need to run the results of the addition operations through a sign function. The sign function returns 1 if the value is positive, 0 if the value is 0, and -1 if the value is negative.

Lets say you wanted to count the clicks for all users between age 20-25:

=ARRAYFORMULA(sum(sign((A:A=20) + (A:A=21) + (A:A=22) + (A:A=23) + (A:A=24) + (A:A=25)) * (C:C="true")))

As Irene Liberali said use COUNTIFS:

=COUNTIFS(A:A,4,C:C,1)

Try:

=sumproduct(A:A="One", B:B=C:C)