Join Delta Table with Same Full Table

[#1]

Hello,

Here is a theoretical Sample Table

Key	Type	Whatever
X	T1	123
Y	T2	456
Z	T3	789

Now there is a change on Key-X and Key-Z, they both become Type-T4

In a transformation flow that works on Delta I'm joining the Delta to the Full Table

The Delta Table would be

Key	Type	Whatever
X	T4	123
Z	T4	789

Now what will be the join result if I do a join on Delta-Type and Full-Type?

Will the engine know NOT to take the records from the Delta in the join, knowing there is a changed version coming along or will it be so smart to join X-Z ?

Becasue based on the original Full table there would be no match for each single record...

I hope I made myself clear 🙂

[Martin_Kuma]

Hi,

HANA Engine, no matter if SQL, Analytics or Calculation will not know and when you join, you have to decide from which table you take the fields Type and Whatever.... 

But... Why Join? I use Union. First select all from Delta and union the results with Select all from Full, where key does not-exist-in-Delta. 

In case your measure: whatever is a stock measure, then you union with Full without the not-exist-in-Delta. 

But that is all. If I did not miss some critical detail from your description, then this is a standard scenario. 

Cheers, Martin