Hi shong,
thanks for your reply.
So if rowA doesn't match rowB, all non nullable fields of rowB get default values ?
0 for integers, "" for Strings, 01/01/1970 for Dates and so on ?
That's really surprising...
So, how can I distinguish the case where rowB did match or not in the following case:
rowA (int id, String name)
0, Peter
1, John
2, Mark
rowB (int id, int amount)
1, 15
2, 10
After a left join I get: (id, name, amount)
0, Peter, 0
1, John, 15
2, Mark, 10
How do I know if Peter has an amount of 0 because it exists in rowB or if Peter doesn't exist in rowB ?