Returns a table with selected columns from the table and new columns specified by the DAX expressions.
The table from which columns are selected.
The name of the new column to be added.
The expression for the new column to be added.
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, 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.
Other related functions are:
Contributors: Alberto Ferrari, Marco Russo
MSDN documentation: https://msdn.microsoft.com/en-us/query-bi/dax/selectcolumns-function-dax