In Redshift I can create a temporary table in two different ways.
Using the TEMPORARY parameter:
CREATE TEMPORARY TABLE tbl...
or by putting a hash at the start of the table name:
CREATE TABLE #tbl...
The Redshift docs have a special red Important box which describes this other method:
If you specify a table name that begins with '#', the table is created as a temporary table.
But they don't say why these two methods exist, and whether one is preferred over the other for any reason.
I assume the #tbl formulation is for historical/backwards compatibility reasons, but it'd be interesting to see what these are.