[mongodb] MongoDB: How to query for records where field is null or not set?

{ "sent_at": null }

Examples related to mongodb

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Examples related to null

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Examples related to mongodb-query

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Examples related to exists

• Select rows which are not present in other table • How to fix "Only one expression can be specified in the select list when the subquery is not introduced with EXISTS" error? • Check if record exists from controller in Rails • sql: check if entry in table A exists in table B • How to exclude records with certain values in sql select • SQL - IF EXISTS UPDATE ELSE INSERT INTO • Linq select objects in list where exists IN (A,B,C) • PL/pgSQL checking if a row exists • How to Check if value exists in a MySQL database • MongoDB: How to query for records where field is null or not set?