[web2py] Using SQL functions in SELECT?

[MichaelF]

Is there a way I can use 'arbitrary' SQL functions in my queries? For 
example, I might want to do something akin to:

SELECT * FROM tbl WHERE Start_date < NOW();

I realize that in this particular case I can translate the "NOW()" SQL 
function to the current date/time. But how about other functions? If I use 
them am I limited to using executesql?

Thanks.

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