Index formula, duplicate records problem

PS Maybe your problem with Haseeb A's solution is because of an unwanted space (typo I'm sure). Try deleting the space from "A14 80".

Hi Estige

thank you for your help

i have used your formula in data, and its saying that there is
17corps
149 chain
1276 – external id ( i checked corpsid, manually and it worked out correct,so i assume chain and external id is also correct) i

is there any way now, i can determine how many externalid go into the chain ?

so how many 1276externalid are linked to the 149 chains ?
and then how many of those chains, so 149, are linked to those 17 corps ?