Dont know exactly what you mean by having a hard time
anyway try something like this ....
Explicitly mention the column names in both selects and use UNION ALL
, use fully qualified names of your tables something like this....
SELECT Column1, Column2, Column3, ..... <Other Column Names>
FROM [Database_Name1].[Schema1].[Table_Name1]
UNION ALL
SELECT Column1, Column2, Column3, ..... <Other Column Names>
FROM [Database_Name2].[Schema1].[Table_Name2]
using this syntax eliminates most of the possible errors.