编辑“︁SQLAlchemy”︁（章节）

=== 查询 ===
<syntaxhighlight lang="Python">
alldata = session.query(Movie).all()
for somedata in alldata:
    print somedata
</syntaxhighlight>

SQLAlchemy将向DBMS发起如下查询（忽略别名）：
<syntaxhighlight lang="SQL">
SELECT movies.id, movies.title, movies.year, movies.directed_by, directors.id, directors.name 
FROM movies LEFT OUTER JOIN directors ON directors.id = movies.directed_by
</syntaxhighlight>

输出结果：
<syntaxhighlight lang="python">
Movie('Star Trek', 2009L, Director('JJ Abrams'))
Movie('Star Wars', 1977L, Director('George Lucas'))
Movie('THX 1138', 1971L, Director('George Lucas'))
</syntaxhighlight>

假如在架构定义时设置<code>lazy=True</code>（默认值），SQLAlchemy将首先发起一个查询来获得一个电影列表，并在必要时（延迟）对每个导演发起查询来获得对应导演的名字：
<syntaxhighlight lang="SQL">
SELECT movies.id, movies.title, movies.year, movies.directed_by 
FROM movies

SELECT directors.id, directors.name
FROM directors 
WHERE directors.id = %s
</syntaxhighlight>