I need to do an union between 2 tables and there is a column on the first table that doesn't exist on the second table, so, I would like to set up a column with null's (e.g: select null as column_name from table2). However, it involves a SUM and I can't use "null as Sum(column_name)" since it doesn't work. Since the values are null, the sum would be 0. So, how do I select a sum from a column that doesn't exist in a table but I will insert null values on that column?

CodePudding user response：

In your union, when you select from the table that does not have the column in question, just include null as <column name> in the appropriate position in your select statement. Or you could do 0 as <column name>, whatever works better for you.

CodePudding user response：

You could apply ZEROIFNULL around that column to make them 0.

SUM(ZEROIFNULL(UnionColumn)) This should work fine with Teradata.