I want to construct a clause by anding the previous clause with new clauses,
and I was wondering if there was a standard way to initialize an empty
clause. First, here's some code that illustrates the general idea of what
I'm trying to do:
clause = True
if cond1:
clause = and_(clause, cond1_clause)
if cond2:
clause = and_(clause, cond2_clause)
and then I execute the select(cols, clause) query.
Is there some better value to initialize clause to? From experimentation,
None as an initial value also does what I want, but initially setting clause
to None then might lead to confusion since it's False in Python and
(roughly, correct me if I'm wrong) True in SQLAlchemy.
Also, is there a good value to initialize clause to in order for code of the
following sort to work? Or is this a bad practice?
clause = some_init_value
if cond1:
clause &= cond1_clause
if cond2:
clause &= cond2_clause
Because the and_ and or_ methods special case the single argument case (just
passing them through), the simplest thing I've found to work is the
and_(True, True) construct. But that's exceedingly hacky imo.
Thanks in advance!
--Darren
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