Hi,
@ETAF
1] Your formula: =IF(B13="","", LOOKUP(2,1/(APOIO!$B$2:$B$1000=B13*1)/(APOIO!$C$2:$C$1000=C13*1),(APOIO!$D$2:$D$1000)))
It is a good formula for 2 criteria Lookup.
However
2] I just suggest a better, shorter and faster format to use Lookup function as similar to yours.
=IF(B13="","",LOOKUP(
9.9E+307,APOIO!$D$2:$D$1000/(APOIO!$B$2:$B$1000=
--B13)/(APOIO!$C$2:$C$1000=
--C13)))
3] Explanation
3.1] Your Lookup formula Lookup method is using: "Vector form."
Syntax: LOOKUP(lookup_value, lookup_vector, [result_vector])
3.2] My Lookup formula Lookup method is using: "Array form."
Syntax: LOOKUP(lookup_value, array)
The lookup_value, I used 9.9E+307 is a BigNum (Please Google of this word)
4] The Lookup formula searching way
4.1] Lookup Vector form: using linear way (Top-down searching way)
4.2] Lookup Array form: using Binary way (1/2>>1/4>>...... searching way, Please Google Binary way)****a very fast search wann
5] Conclusion
Lookup "Array form" is faster than Lookup "Vector form" a very long distance.
So,
Array form > Vector form
6] Remark
6.1] If the [result_vector] is Number, you need to use:
LOOKUP(9.9E+307,[result_vector]/(Condition 1)/(Condition 2))
6.2] If the [result_vector] is Text, you need to use:
LOOKUP(2,1/(Condition 1)/(Condition 2),[result_vector])
Regards
Bosco