Nested subqueries in Hive are used to perform complex data analysis by nesting one query inside another. A subquery is a query that is nested inside another query, and it is used to retrieve data that will be used in the main query.
Hive supports nested subqueries in the WHERE, HAVING, and FROM clauses. The subquery can be a SELECT, VALUES, or TABLE clause that returns a single value, a single row, or a table.
Nested subqueries can also be used in the HAVING and FROM clauses to perform more complex analysis. It’s important to note that the use of subqueries can impact query performance, and it’s recommended to use them only when necessary.
In summary, nested subqueries in Hive are a powerful feature that allows for complex data analysis by nesting one query inside another. They can be used in the WHERE, HAVING, and FROM clauses and can be a SELECT, VALUES, or TABLE clause that returns a single value, a single row, or a table.