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How to write Subqueries and Joins in MongoDB?
What is Subquery? A subquery is query inside an INSERT,UPDATE,SELECT,DELETE statements. It can also be nested inside another subquery. It can be used anywhere an expression is allowed. Example: SELECT * FROM CUSTOMERS WHERE ID IN (SELECT ID FROM CUSTOMERS WHERE SALARY > 4500) ; INSERT INTO CUSTOMERS_BKP SELECT * FROM CUSTOMERS WHERE ID IN (SELECT ID FROM CUSTOMERS)…