Database
[{"tag":"tag2","date":"2022-07-18","userId":"1","postId":"12"},{"tag":" ","date":"2022-07-18","userId":"1","postId":"12"},{"tag":" ","date":"2022-07-18","userId":"2","postId":"12"}]
Query
db.collection.find({$and:[{$or:[{tag:"tag2"},{tag:" "}]},{$or:[{userId:"1"},{userId:" "}]}]})