SWQL Queries - Merging two tables

Hi all,

I have difficulty in using SWQL (since i don't have any background in SQL at all ).

I would like to merge two different table,where there is one common column (InterfaceID), but the queries have to display InterfaceID which only have Comments "WAN vrf" on the second table..

Found some similar topic in google but for SQL, so i try below syntax :

SELECT NodeID, InterfaceID, Caption, FullName, Alias, IfName

FROM Orion.NPM.Interfaces

UNION SELECT InterfaceID, Comments

FROM Orion.NPM.InterfacesCustomProperties

WHERE Comments='WAN vrf'

however when i try above, it return with mismatched input 'SELECT' expectin '('

I'm not really sure how to correct the syntax. Appreciate much for any help here.

Thanks and regards

Adi