The SendGrid table Recipients.
SendGrid has the ability to categorize Recipients with filters defined by the user. Accordingly, you can execute statements to the Recipients table to search by and insert these filters. However, these filters are reported as attributes of the Custom Fields table.
The following query retrieves only the default fields of the Recipients table, not the Custom Fields that you have created. To retrieve the values of the Custom Fields of a Recipient, query the Custom Fields table.\
You can also retrieve all Recipients inside a certain List or a Segment, but it is not possible to filter by both. Use multiple queries instead:\
You can build criteria depending on a Custom Field. When querying use quotations regardless of type.This kind of filtering is done client side. In this case Age is a CustomField created by the user.\
To insert into Recipients Email is required.
You can insert Custom Fields into the Recipients table. See the CustomFields section for more information about how to create custom fields.\
You can only update from this table by specifying an Id. Additionally, the Email column cannot be updated.\
You can only delete from this table by specifying an Id.\
Pseudo column fields are used in the WHERE clause of SELECT statements and offer a more granular control over the tuples that are returned from the data source.