mixing ingredients from tables besides looping

I want to add certain percentages of data from several tables to one new table. The percentage of the ingredients added up should equal to 100%. The percentage of each ingredient can be from 0% to 100%. I need to go through and save all the possible compositions with distinct names, and do calculations in order to find out the best composition. For example, 10% database A + 90% database B + 0% database C, 10% database A + 80% database B + 10% database C, 10% database A + 70% database B + 20% database C, ...

Starting with two databases A and B, each with 4 columns of numerical data. I will need to produce and save all the mixed combination. For example, 10% of each column in A add 90% of the corresponding column in B, and save the result. The total percentage is 100%. This could be done with loop. for x=0:0.1:1, C=x*A+(1-x)*b, end. This seems straightforward, if I only have two databases A and B.

If I have three databases, A, B and C, to produce D. So I need two loops?

If I have A, B, C and D, to produce E, so I need to have three loops?

If I want to mix more, do I have to create another loop again?

As the number of the databases I want to mix increase, this looping solution seems inefficient. Because everytime the numer of database changes, I need to rewrite my code again.

I was wondering if there is any better solution for this problem. So it does not need me to redo the coding even if I change the number of databases to be mixed. I hope I only need one code to run whatever number of databases that I want to mix.

Thank you very much.