[英]Pymongo: How to query MongoDB for existing and non-empty string field?
This is a great answer to the question "how to query for an existing and non-null field". 这是对“如何查询现有的非空字段”这个问题的很好的答案 。 But I also need to check that a field is not an empty string. 但是我还需要检查一个字段是否不是空字符串。 So the complete query needs to check that: 因此,完整的查询需要检查以下内容:
What's the best way to do that? 最好的方法是什么?
Use {'$nin': [None, '']}
: 使用{'$nin': [None, '']}
:
col.insert({})
col.insert({'test_field': None})
col.insert({'test_field': ''})
col.insert({'test_field': 'value'})
list(col.find({'test_field': {'$exists': True}}))
[{u'_id': ObjectId('5b293fa7b5b55217c9afe7d0'), u'test_field': None},
{u'_id': ObjectId('5b293fb1b5b55217c9afe7d2'), u'test_field': u''},
{u'_id': ObjectId('5b293fb6b5b55217c9afe7d3'), u'test_field': u'value'}]
list(col.find({'test_field': {'$ne': None}}))
[{u'_id': ObjectId('5b293fb1b5b55217c9afe7d2'), u'test_field': u''},
{u'_id': ObjectId('5b293fb6b5b55217c9afe7d3'), u'test_field': u'value'}]
list(col.find({'test_field': {'$nin': [None, '']}}))
[{u'_id': ObjectId('5b293fb6b5b55217c9afe7d3'), u'test_field': u'value'}]
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