问题
I am a new bee with the Datastore gCloud. And I want to filter in an entity called Score all the scores that have relation with a list of companies. My entity is formed as follows:
{
"company_id": 1,
"score": 100,
}
I have several entities with different company IDs. I tried to filter using the query.add_filter command but got the error ValueError:
('Invalid expression: "IN"', 'Please use one of: =, <, <=,>,> =.')
The reason for the error is very clear to me, but I have not found anything in the documentation on how to run filters with IN or CONTAINS, in addition to types other than those listed in the above error message.
回答1:
The filters operators you seek are not supported by the datastore. The only supported ones are listed in Filters:
The comparison operator can be any of the following:
Operator Meaning EQUAL Equal to LESS_THAN Less than LESS_THAN_OR_EQUAL Less than or equal to GREATER_THAN Greater than GREATER_THAN_OR_EQUAL Greater than or equal to
Some of the client libraries may offer some equivalents, but with limitations. For example the standard environment GAE-specific ndb library (not usable in your context) offers such support. The example from The != and IN Operations can be useful as you can implement it in a similar manner in your code:
Similarly, the IN operation
property IN [value1, value2, ...]which tests for membership in a list of possible values, is implemented as
(property == value1) OR (property == value2) OR ...
来源：https://stackoverflow.com/questions/49582670/gcloud-datastore-can-i-filter-with-in-or-contains-operator