LOOKUPVALUE Returns the value in result_columnName for the row that meets all criteria specified by search_columnName and search_value.
LOOKUPVALUE( result_columnName, search_columnName, search_value[, search_columnName, search_value]…[, alternateResult])
Result_columnName -The name of an existing column that contains the value you want to return. The column must be named using standard DAX syntax, usually, fully qualified. It cannot be an expression.
Search_columnName – The name of an existing column, in the same table as result_columnName or in a related table, over which the look-up is performed. The column must be named using standard DAX syntax, usually, fully qualified. It cannot be an expression.
Search_value – A scalar expression that does not refer to any column in the same table being searched.
AlternateResult – (Optional) The value returned when the context for result_columnName has been filtered down to zero or more than one distinct value. When not provided, the function returns BLANK() when result_columnName is filtered down to zero value or an error when more than one distinct value.
The value of result_column at the row where all pairs of search_column and search_value have a match.