* SQL-92 Table Creation Script with DBISAM Extensions */

CREATE TABLE IF NOT EXISTS "Payments"
(
   "Amount" MONEY,
   "TypeID" INTEGER
LANGUAGE "ANSI Standard" SORT "Default Order"
USER MAJOR VERSION 1
);

INSERT INTO "Payments" VALUES (100 , 1) NOAUTOINC;
INSERT INTO "Payments" VALUES (50 , 2) NOAUTOINC;
INSERT INTO "Payments" VALUES (150 , 3) NOAUTOINC;
INSERT INTO "Payments" VALUES (200 , 1) NOAUTOINC;

CREATE TABLE IF NOT EXISTS "PaymentTypes"
(
   "ID" AUTOINC,
   "IsCash" BOOLEAN
LANGUAGE "ANSI Standard" SORT "Default Order"
USER MAJOR VERSION 1
);

INSERT INTO "PaymentTypes" VALUES (1 , True) NOAUTOINC;
INSERT INTO "PaymentTypes" VALUES (2 , False) NOAUTOINC;
INSERT INTO "PaymentTypes" VALUES (3 , True) NOAUTOINC;

CODE TO REPRODUCE ERROR:

select sum(P.Amount) as SumAmount
from Payments P
join PaymentTypes PT on (PT.ID = P.TypeID)
where PT.IsCash = true

WORKAROUND:

select 1 as InternalDummyID,
sum(P.Amount) as SumAmount
from Payments P
join PaymentTypes PT on (PT.ID = P.TypeID)
where PT.IsCash = true
group by InternalDummyID