我向 psql 编写了原始查询,它工作正常,但是当我在 sqlalchemy 中编写此查询时,我的 WHERE 子句复制到 FROM 子句。
select id from T1 where arr && array(select l.id from T1 as l where l.box && box '((0,0),(50,50))');
在此查询中,我从 T1 获取所有 id,其中带有整数的数组与子查询的结果相交。
class T1():
arr = Column(ARRAY(Integer))
...
class T2():
box = Column(Box) # my geometry type
...
1 验证:
layers_q = select([T2.id]).where(T2.box.op('&&')(box)) # try find all T2 intersects with box
chunks = select([T1.id]).where(T1.arr.overlap(layers_q)) # try find all T1.id where T1.arr overlap with result from first query
SELECT T1.id
FROM T1
WHERE T1.arr && (SELECT T2.id
FROM T2
WHERE T2.box && %(box_1)s)
我有一个关于类型转换的 PG 错误。我明白。
2版本:
layers_q = select([T2.id]).where(T2.box.op('&&')(box))
chunks = select([T1.id]).where(T1.arr.overlap(func.array(layers_q)))
I added 函数.array()用于转换为数组但结果不正确:
SELECT T1.id
FROM T1, (SELECT T2.id AS id
FROM T2
WHERE T2.box && %(box_1)s)
WHERE T1.arr && array((SELECT T2.id
FROM T2
WHERE T2.box && %(box_1)s))
在那里你可以看到我在 FROM 子句中重复的内容。怎么做才正确呢?