WHERE is subquery hive?

Hive supports subqueries in FROM clauses and in WHERE clauses of SQL statements. A subquery is a SQL expression that is evaluated and returns a result set. Then that result set is used to evaluate the parent query. The parent query is the outer query that contains the child subquery.

Can we use SQL in hive?

Using Apache Hive queries, you can query distributed data storage including Hadoop data. Hive supports ANSI SQL and atomic, consistent, isolated, and durable (ACID) transactions. You use familiar insert, update, delete, and merge SQL statements to query table data. The insert statement writes data to tables.

What are the advantages of using sub queries provided by Hive?

Advantages Of Subquery:

• Subqueries divide the complex query into isolated parts so that a complex query can be broken down into a series of logical steps.
• It is easy to understand and code maintenance is also at ease.
• Subqueries allow you to use the results of another query in the outer query.

Does Hive support with clause?

A Hive WITH Clause can be added before a SELECT statement of you query, to define aliases for complex and complicated expressions that are referenced multiple times within the body of the SELECT statements.

What is CTE in hive?

A Common Table Expression (CTE) is a temporary result set derived from a simple query specified in a WITH clause, which immediately precedes a SELECT or INSERT keyword. One or more CTEs can be used in a Hive SELECT, INSERT, CREATE TABLE AS SELECT, or CREATE VIEW AS SELECT statement.

What is left semi join in hive?

The left semi join is used in place of the IN / EXISTS sub-query in Hive. In a traditional RDBMS, the IN and EXISTS clauses are widely used whereas in Hive, the left semi join is used as a replacement of the same. table_reference : Is the table name or the joining table that is used in the join query.

Why use subqueries instead of joins?

If you need to combine related information from different rows within a table, then you can join the table with itself. Use subqueries when the result that you want requires more than one query and each subquery provides a subset of the table involved in the query.

Does Hive support recursive CTE?

Hive support with clause, but hive does not support Recursive Queries.