python - how to check if value return in plpython query? -

i have assignment in plpythonu in postgresql function:

result=plpy.execute("select  value table  doctitle '%%%s%%'"%projectname) if result:     final = result[0]["value"] 

the query can return 1 text result or nothing.

the issue if query returned nothing if result: condition still true (cuz contains value column)... want assignment final happen if there actual value in value column. how check that?

the result object emulates list or dictionary object. check length:

if len(result) > 0: 

but test should work empty list or dictionary evaluates false:

create or replace function p() returns boolean $$  result = plpy.execute('select 1 false') if result: return true else: return false  $$ language plpythonu; 

returns false:

select p();  p  ---  f 

pass parameters execute in instead of substitute yourself. otherwise vulnerable sql injection:

query = """     select value     table     doctitle format('%%%s%%', $1) """ plan = plpy.prepare(query, ["text"]) result = plpy.execute(plan, [_text_parameter]) if result:     final = result[0]["value"] 

https://www.postgresql.org/docs/current/static/plpython-database.html