TextCount(If([Current Status] = 'Filled', [Requisition Filled Date] >= MakeDate(2018,8,1), [Aged Requisitions])) as [Filled]
Also, In the discussion, you have not mentioned the other columns and Groupby. TextCount() requires groupby.
I actually want a script to know the count of aged requisitions for this two condition: Current Status=Filled and Requisition Filled Date from 1/1/2018
Aged Requisitions, Current Status, Requisition filled Date are the columns
Try doing it the other way round then.
LOAD * INLINE [
Aged Requisitions, Current Status, Requisition Filled Date
A, Filled, 9/17/2017
B, Not Filled, 9/18/2018
C, Filled, 9/19/2017
A, Filled, 9/20/2018
B, Not Filled, 9/21/2017
C, Filled, 9/22/2018
A, Not Filled, 9/23/2018
B, Filled, 9/24/2018
C, Filled, 9/25/2018
A, Filled, 9/26/2017
B, Filled, 9/27/2018
C, Filled, 9/28/2018
A, Filled, 9/29/2018
B, Not Filled, 9/30/2018
Count( Distinct RecNo()) as Count1
[Current Status] = 'Filled'
and [Requisition Filled Date] >= Date(YearStart(Today()))
Group By [Aged Requisitions];
DROP Table Source;
Let me know if this works for you.