Nest CHOOSECOLS inside UNIQUE to extract non-adjacent columns, and use INDIRECT for interactive header dropdowns.
The default method for including a column reference in an Excel formula is to use the column letter, a convention that may make it difficult to interpret the parts of complex formulas. Microsoft ...
Excel has over 475 formulas in its Functions Library, from simple mathematics to very complex statistical, logical, and engineering tasks such as IF statements (one of our perennial favorite stories); ...