Python 在peewee中加入子查询
我一直在将下面的查询转换为peewee:Python 在peewee中加入子查询,python,peewee,Python,Peewee,我一直在将下面的查询转换为peewee: SELECT bID, taskCount FROM ( SELECT block.id AS bID, Count( task.id ) AS taskCount FROM block LEFT JOIN task ON task.block_id = block.id WHERE block.id NOT IN ( ( SELECT
SELECT bID, taskCount
FROM
(
SELECT
block.id AS bID,
Count( task.id ) AS taskCount
FROM
block
LEFT JOIN task ON task.block_id = block.id
WHERE
block.id NOT IN ( ( SELECT task.block_id FROM task WHERE task.channel_id = '1' ) )
GROUP BY
block.id
) AS A
INNER JOIN ( SELECT task.block_id FROM task GROUP BY task.block_id ) AS B
我知道这是可以做到的,但我无法编写完整的解决方案,因为我不知道如何处理别名(BID、TaskCount),然后在哪里使用连接
这是我写的,显然不起作用:
subquery1 = (Block.select(Block.id.alias('BID'),fn.COUNT(Task.id).alias('TaskCount'))
.join(Task,JOIN.LEFT_OUTER,Task.block_id == Block.id)
.where(Block.id.not_in(Task.select(Task.block_id).where(Task.channel_id=='1')))
.group_by(Block.id)
.alias('subquery1'))
subquery2 = (Task.select(Task.block_id).group_by(Task.block_id) )
query = subquery1.select(subquery1.c.BID,subquery1.c.TaskCount)
.join(subquery2, on=(subquery1.c.BID == subquery2.c.block_id))
编辑:我修正了一些错误。但现在我应该从查询对象中得到什么?!!
如果打印查询的行,我将面临:
peewee.InternalError: (1054, "Unknown column 'subquery1.BID' in 'field list'")
我发现您在开始的查询中缺少一些信息。您应该指定:
- 在“from”中,字段是否来自select语句A或B
- 在“内部联接”中,使用哪些字段映射select语句。例如,从B中选择A,B。在B.field=A.field上内部连接A李>
我自己对Peewee并不熟悉,但希望这会有所帮助。最后,在上下波动后,我注意到一个问题,我的代码中有一个额外的部分被我删除了
subquery2 = (Task.select(Task.block_id).group_by(Task.block_id) )
query = subquery1.select(subquery1.c.BID,subquery1.c.TaskCount).join(subquery2, on=(subquery1.c.BID == Task.block_id))
正确的部分是:
subquery1 = (Block
.select(Block.id.alias('BID'),fn.COUNT(Task.id).alias('TaskCount')
).join(Task,JOIN.LEFT_OUTER,Task.block_id == Block.id)
.where(Block.id.not_in(Task.select(Task.block_id).where(Task.channel_id=='1')))
.group_by(Block.id)
.alias('subquery1')).order_by(fn.COUNT(Task.id))
您共享的SQL是否实际执行并执行您期望的操作?对我来说,它看起来非常糟糕。是的,虽然sql代码工作得很好,但我认为它写得有点不标准!没有什么建议吗?