I\'m trying to have a similar function to SUMIFS (like SUMIF but with more than a single criterion) in a Google Spreadshe
This guy used the Filter function to chop down the array by the criteria, then the sum function to add it all in the same cell. http://www.youtube.com/watch?v=Q4j3uSqet14 It worked like a charm for me.
As of December, 2013, Google Sheets now has a SUMIFS function, as mentioned in this blog post and documented here.
Note that old spreadsheets are not converted to the new version, though you can try copy-pasting the data into a new workbook.
I found a faster function to fill up the "pivot table":
=ARRAYFORMULA(SUM(((Sample!$A:$A)=$A2) * ((Sample!$B:$B)=B$1) * (Sample!$C:$C) ))
It seems to run much faster without the heavier String and Query functions.
The simplest way to easily make SumIFS-like functions in my opinion is to combine the FILTER and SUM function.
SUM(FILTER(sourceArray, arrayCondition_1, arrayCondition_2, ..., arrayCondition_30))
For example:
SUM(FILTER(A1:A10;A1:A10>5;B1:B10=1)
Explanation: the FILTER() filters the rows in A1:A10 where A1:A10 > 5 and B1:B10 = 1. Then SUM() sums the values of those cells.
This approach is very flexible and easily allows for making COUNTIFS() functions for example as well (just use COUNT() instead of SUM()).