我有这个 SQL 表达式：
SELECT count(*), date_trunc('day', data)
from (
select max(hc.acesso) as data
from historico_comunicacao hc
join cliente c on (c.id = hc.id_cliente)
group by c.id
having max(hc.acesso) between ('2012-11-30') and ('2012-12-07 23:59:59')
order by max(hc.acesso) desc
) as x
GROUP BY 2
ORDER BY 2 DESC;
所以，我在 SqlAlchemy 中这样做了：
nestedQuery = session.query(func.max(MapComunicacao.acesso).label('data'))\
.join(MapCliente)\
.group_by(MapCliente.id)\
.having(func.max(MapComunicacao.acesso).between(dataini, dataFinal))\
.order_by(desc(func.max(MapComunicacao.acesso)))
query = session.query(
func.count(nestedQuery.subquery().columns.data),
extract('day', nestedQuery.subquery().columns.data)
)\
.group_by('anon_3.data')
result = query.all()
没有发生错误，但返回的数据对我来说是错误的。
我有两个表：Cliente (Customer) 和 Historico_Acesso (Access_History)。我想知道的是最后一次与我的数据库交谈的客户总数，按日期分组。
像这样：
总日期
19; “2012-12-07 00:00:00+00”
16; “2012-12-06 00:00:00+00”
20; “2012-12-05 00:00:00+00”
06; “2012-12-04 00:00:00+00”
06; “2012-12-03 00:00:00+00”
01; “2012-12-02 00:00:00+00”
04; “2012-12-01 00:00:00+00”
09; “2012-11-30 00:00:00+00”