Q: I have a point dataset A with 500 records and a point dataset B with 100 records (the 100 records are contained in the dataset A). How can I extract the other 400 records form the dataset A?

A: Create a new field aa in B, and set a unified value (such as 1) for all records. You must ensure that the two datasets have an associated field such as name or other fields. Perform sql query on dataset A, associate the two datasets with the associated field, and then query aa=1 to get the 100 records in dataset A. You can directly delete the 100 records and leave the 400 records.