Table 2

column1 column2 column3
row1 a a a
row2 b b b
row3 c d
row4 d

Now i'm trying to put a formula such that from table 2, if column 1 is referred, it should then refer to table 1 and pick corresponding values from either column 1 or 2 and add the values and give results - in above case, if from table 2, column 3 is selcted, then i shoudl get the result as (1+3 = 4 or 2+4 = 6 depending on what column is required to be referred in table 1.

I simplified the formula to make it easier to read.

But you could also create named ranges for each table, I tried and it works.

Great, works like a charm!
One question more,is the "formula_tbl_1" an example-shortcut of writing this
INDEX(B2:F4, MATCH(C11, A2:A4, 0), MATCH(C12, B1:F1, 0))), INDEX(B7:E8, MATCH(C11, A7:A8, 0), MATCH(C12, B6:E6)

Or there is a way, to name your formula, like named ranges?

Yes!

I removed some brackets.

I try the function,now with 4 tables!And I guess that is something like this

=IF(ISERROR(formula_tbl_1)), IF(ISERROR(formula_tbl_2)), IF(ISERROR(formula_tbl_3)), formula_tbl_4),formula_tbl_3)formula_tbl_2), formula_tbl_1)

Right?

For one more time,thank you very much!

Two index functions:
=IF(ISERROR(formula_tbl_1)), formula_tbl_2, formula_tbl_1)

Three index functions:
=IF(ISERROR(formula_tbl_1)), IF(ISERROR(formula_tbl_2)), formula_tbl_3), formula_tbl_2), formula_tbl_1)

Hello again!
Is there a "logic-form" for above 3 tables?Always with the if(iserror)?

thanks.

The iferror function is easier.

You are GREAT!The God of the excel...i try to convert to if(iserror)
but I forget the third Index...witch i believe make the difference!

And I think with the If(iserror is more easy for above the 3 tables right?