Delphi - ClientDataSet SQL calculated field causing "Invalid field type" error at runtime

I have a ClientDataSet which loads its data from a table in a SQLite database using a TFDQuery.

The SQL query selects fields from a table of bank accounts: the AccountID, Name, StartBalance and CurrentBalance. CurrentBalance is a calculated field.

This is the query:

SELECT 
  p1.AccountID, 
  p1.Name, 
  p1.StartBalance,
  cast(
    p1.StartBalance 
    + (SELECT TOTAL(Amount) 
       FROM Trx p2
       WHERE (p2.AccountID1 = p1.AccountID
              AND p2.TrxType = 'income')
          OR (p2.AccountID2 = p1.AccountID
              AND p2.TrxType = 'transfer'))
    - (SELECT TOTAL(Amount) 
       FROM Trx p3
       WHERE p3.AccountID1 = p1.AccountID
         AND (p3.TrxType = 'expense' OR p3.TrxType = 'transfer'))
   as Currency) AS CurrentBalance
FROM Account p1;

This query runs perfectly well and produces the expected results. Also, when there are existing records in the Account table, I am able to successfully load the results into a ClientDataSet with the following FieldDefs:

• AccountID (ftInteger)
• Name (ftString)
• StartBalance (ftCurrency)
• CurrentBalance (ftCurrency)

However, when there are no records in the table and I attempt to open the ClientDataSet (cdsAccount.Open), I receive the runtime error: "Invalid field type". If I remove the calculated field (CurrentBalance) from both the query and the ClientDataSet's FieldDefs, then no error is produced.