Question

我正在尝试从虚构的汽车及其所有者表中检索“ id_owner”列表（例如“ id”，“ owner_id”，“ carname”）。此所有者列表应包含其他列表中的所有汽车。

应为： SELECT id_owner FROM ownedcars WHERE carname = "Ferrari" or carname = "Mustang" or carname = "Porsche"

我认为需要在子查询中执行此操作，因为我尝试了所有方式，该列表返回了包含此列表中任何汽车的所有id_owners，而不是包含列表中的所有三辆汽车

Answer 1

这可以通过def _maybe_dedup_names(self, names): if self.mangle_dupe_cols: names = list(names) # counts = defaultdict(int) counts = defaultdict(lambda:1) # So that your duplicated column suffix starts with 2 not 1 is_potential_mi = _is_potential_multi_index(names) for i, col in enumerate(names): cur_count = counts[col] while cur_count > 0: counts[col] = cur_count + 1 if is_potential_mi: # col = col[:-1] + ('%s.%d' % (col[-1], cur_count),) col = col[:-1] + ('%s%d' % (col[-1], cur_count),) else: # col = '%s.%d' % (col, cur_count) col = '%s%d' % (col, cur_count) # eliminate '.' from formating cur_count = counts[col] names[i] = col counts[col] = cur_count + 1和group by完成。

having

Answer 2

我认为它需要在子查询中完成，因为我一直尝试过，该列表将返回包含此车中任何一个的所有id_owners 列表，而不是包含列表中的所有三辆车

根据以上消息，您可以使用EXISTS运算符实现您的目标。

SELECT id_owner FROM ownedcars T
WHERE EXISTS (SELECT 1 FROM ownedcars WHERE carname='Ferrari' AND id_owner=T.id_owner)
AND EXISTS (SELECT 1 FROM ownedcars WHERE carname='Mustang' AND id_owner=T.id_owner)
AND EXISTS (SELECT 1 FROM ownedcars WHERE carname='Porsche' AND id_owner=T.id_owner)

最好的问候，

会

SQL如何从列表中选择包含所有汽车的“ id_owner”

2 个答案: