What is a "leaf expression"?
Partition-clause expressions are limited in the following ways:
Your partition-clause must calculate a single non-null value for each row. You can reference multiple columns, but each row must return a single value.
You can specify leaf expressions, functions, and operators in the partition clause expression.
All leaf expressions in the partition clause must be either constants or columns of the table.
Source https://my.vertica.com/docs/6.1.x/HTML/index.htm#18125.htm
CURRENT_TIMESTAMP()
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– ypercube Nov 4 '13 at 15:57