This is a limitation of Google's original Java implementation of the aggregation functions. While most SQL engines can easily support complex expressions in aggregation functions, the library's query engine currently does not and will only accept a column name as the argument. Support for complex expressions would take a major rewrite (I think).
Working example: SELECT SUM(x)
Non-working example: SELECT SUM(x + 1)
This is a limitation of Google's original Java implementation of the aggregation functions. While most SQL engines can easily support complex expressions in aggregation functions, the library's query engine currently does not and will only accept a column name as the argument. Support for complex expressions would take a major rewrite (I think).
Working example:
SELECT SUM(x)Non-working example:
SELECT SUM(x + 1)