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So vereinigen Sie zwei Unterabfragen in SQLAlchemy und postgresql

Ich habe einen etwas anderen Ansatz verwendet:

# the first subquery, select all ids from SOME_TABLE where some_field is not NULL
s1 = select([SOME_TABLE.c.id]).where(SOME_TABLE.c.some_field != None)

# the second subquery, select all ids from SOME_TABLE where some_field is NULL
s2 = select([SOME_TABLE.c.id]).where(SOME_TABLE.c.some_field != None)

# union s1 and s2 subqueries together and alias the result as "alias_name"
q = s1.union(s2).alias('alias_name')

# run the query and limit the aliased result to 10
session.query(q).limit(10)

Hier ist die erzeugte SQL:

SELECT alias_name.id AS alias_name_id 
FROM (SELECT some_table.id AS id 
FROM some_table 
WHERE some_table.some_field IS NOT NULL UNION SELECT some_table.id AS id 
FROM some_table 
WHERE some_table.some_field IS NULL) AS alias_name 
LIMIT 10

Ich denke, das ist das gewünschte Ergebnis.