join very big number of rows


My task is arrived to a node with 1M of rows. Now i need to join these rows with a table stored into the db with a very high number of rows. I can't insert a database reader on this table therefore the only way is to create a temporary table into the db with the 1M of rows. Then i can insert a databse reader with a join inside.

If i can't stored a temporary table, has anyone another solution?