A column value of type List or EnumList with a base type of Ref can be dereferenced to produce a new list of the values from dereferencing each individual reference, an operation called a list dereference.
A list dereference is performed by enclosing the Ref list column name (such as Related Orders) and the column name of the desired column value (such as Order Date) each in square brackets ([ ]) and placing them adjacent to each other.
For example:
[Related Orders][Order Date]The result will be a list of Order Date column values from the rows identified by the list in the Related Orders column value.
SELECT() expression (assuming the referenced table is Orders and its key column is Order ID):SELECT(
Orders[Order Date],
IN([Order ID], [_THISROW].[Related Orders])
)Sort by another column
To gather a list of column values sorted by a different column value, use the App formula expression of a column to generate a list of row references in the desired order.
For example, for a column named Next Two Weeks, gather the list of rows from the Events table with a Date within the next 14 days, and order the rows by Date from earliest to latest:
ORDERBY(
FILTER(
"Event",
([Date] < (TODAY() + 14))
),
[Date]
)A list dereference can then be used to get the desired list of column values in that same order:
[Next Two Weeks][Event Name]The resulting list of dereferenced values will be in the same order as the original reference list.
See also: Date and time expressions, FILTER(), ORDERBY(), TODAY()