How does the SELECTCOLUMNS function (DAX) work?

The SELECTCOLUMNS function (DAX) adds calculated columns to the given table or table expression.

SELECTCOLUMNS Formula Syntax

SELECTCOLUMNS (
<table>, <name>, <scalar_expression>, [<name>, <scalar_expression>] …
)

How do you use the SELECTCOLUMNS function?

The SELECTCOLUMNS function simply takes some column / columns from another table and create a new table from them.

Considerations when using the SELECTCOLUMNS function

A table with the same number of rows as the table specified as the first argument. The returned table has one column for each pair of <name>, <scalar_expression> arguments, and each expression is evaluated in the context of a row from the specified <table> argument.

SELECTCOLUMNS has the same signature as ADDCOLUMNS, and has the same behavior except that instead of starting with the <table> specified, SELECTCOLUMNS starts with an empty table before adding columns.