the implicit behavior might lead to confusion later on. such as:
from sqlalchemy import *
from sqlalchemy.sql import table, column
t1 = table("t1", column("c1"), column("c2"))
t2 = table("t2", column("c1"), column("c2"))
s1 = select([t1, t2], use_labels=True)
s2 = select([t1, t2], use_labels=True).alias()
print select([s1.c.t1_c1, s1.c.t1_c2])
print select([s2.c.t1_c1, s2.c.t1_c2])
s3 = select([s1.c.t1_c1, s1.c.t1_c2], use_labels=True).alias()
s4 = select([s2.c.t1_c1, s2.c.t1_c2], use_labels=True).alias()
print s3.c.t1_c1
print s4.c.t1_c1 # error - the columns are anonymously named
Manlio Perillo wrote:
>
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>
> Hi.
>
> I have noted that with this query:
>
> # query is the original query
> # query_aux is the query required to compute the number of rows returned
> # by the original query
> query_aux = sql.select(
> [sql.func.count()], from_obj=[query])
>
>
> I get, with PostgreSQL 8.3.7 (and SQLALchemy from trunk):
>
> ProgrammingError: (ProgrammingError) subquery in FROM must have an alias
> HINT: For example, FROM (SELECT ...) [AS] foo
>
>
> The solution is to explicitly add an alias
> query_aux = sql.select(
> [sql.func.count()], from_obj=[query.alias('subquery')])
>
>
> However IMHO this should be done by SQLALchemy, and not by the programmer.
>
> What do you think?
>
>
>
> Thanks Manlio Perillo
>
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