Who can explain this/help us get the right results? We are trying to get the sums of the values from the two children - but the return set brings back more than expected. If you take off the sums and group by's you can see what is being returned.
Same in vfp6,7,8 and SQL Server

CREATE CURSOR __parent (ipkey i)
APPEND BLANK
replace ipkey WITH 001

CREATE CURSOR __child1 (ifk i, namount1 n(10))
APPEND BLANK
replace ifk WITH 001
replace namount1 WITH 1000

APPEND BLANK
replace ifk WITH 001
replace namount1 WITH 1000


CREATE CURSOR __child2 (ifk i, namount2 n(10))
APPEND BLANK
replace ifk WITH 001
replace namount2 WITH 2000

APPEND BLANK
replace ifk WITH 001
replace namount2 WITH 2000

APPEND BLANK
replace ifk WITH 001
replace namount2 WITH 2000

SELECT sum(__child1.namount1) as __c1, sum(__child2.namount2) as __c2;
FROM __parent;
left OUTER JOIN __child1 ON __parent.ipkey = __child1.ifk;
left OUTER JOIN __child2 ON __parent.ipkey = __child2.ifk;
GROUP BY __parent.ipkey