Boris wrote:
Hi, i have trouble creating a customer list. here's the problem.

Customer
Alex
Bill
Cindy
Kelvin
Alex
Alvin
Bill
...

Imagine I have more than thousands entry, what formula should I use to
immediately obtain the list of customers i have?

Thanks,
Boris

One of:

[1] Run Advanced Filter on the Customer column with the Copy to another
location and Unique records only options checked.

[2] Invoke an efficient formula system...

Let A2:A8 house the sample you provided with the Customer label in A2.

In B1 enter a 0.

In B2 enter: Idx [ which is just a label ]

In B3 enter & copy down:

=IF((A3<"")*ISNA(MATCH(A3,$A$2:A2,0)),LOOKUP(9.99 999999999999E+307,$B$1:B2)+1,"")

In C1 enter:

=LOOKUP(9.99999999999999E+307,B3:B65536)

In C2 enter: D-Customer [ which is just a label, D stands for Distinct ]

In C3 enter & copy down:

=IF(ROW()-ROW(C$3)+1<=$C$1,LOOKUP(ROW()-ROW(C$3)+1,B:B,A:A),"")