Internal tables Map Join in Hive is also Called Map Side Join in Hive. The following query executes JOIN on the CUSTOMER and ORDER tables, and retrieves the records: hive> SELECT c.ID, c.NAME, c.AGE, o.AMOUNT > FROM CUSTOMERS c JOIN ORDERS o > ON (c.ID = o.CUSTOMER_ID); In SQL, MINUS is also called EXCEPT. However, there are many more insights of Apache Hive Map join. An SQL JOIN clause is used to combine rows from two or more tables, based on a common field between them. A JOIN condition is to be raised using the primary keys and foreign keys of the tables. The MINUS operator finds the difference between two tables or sub-queries and return results from only first SELECT statement.
The joining condition can be on the common columns between participating tables. Fundamentally, there are two types of tables in HIVE – Managed or Internal tables and external tables. DBA_HIVE_TABLES provides information about all the Hive tables in the Hive metastore. In the non-full outer join case, this is the other table in the Join. During Join predicate. Join is a condition used to combine the data from 2 tables. There are multiple ways to load data into Hive tables. The functionalities such as filtering, joins can be performed on the tables. After Join predicate. In this particular usage, the user can copy a file into the specified location using the HDFS put or copy commands and create a table pointing to this location with all the relevant row format information. For full outer joins both tables are also Null Supplying tables. As discussed the basics of Hive tables in Hive Data Models, let us now explore the major difference between hive internal and external tables. In Apache Hive, there is a feature that we use to speed up Hive queries.Basically, that feature is what we call Map join in Hive. In Apache Hive, while the tables are large and all the tables used in the join are bucketed on the join columns we use Hive Bucket Map Join feature.Moreover, one table should have buckets in multiples of the number of buckets in another table in this type of join. Objective. Introduction to Map Join in Hive. You may get the requirement to choose the joining values based on certain conditions. Introduction to Bucket Map Join. In this article, we are going to discuss the two different types of Hive Table that are Internal table (Managed table) and External table. SQL SET Operator MINUS Alternative in Hive. The user can create an external table that points to a specified location within HDFS . For example, in 'R1 join R2 on R1.x = 5' the predicate 'R1.x = 5' is a During Join predicate. Requirement You have two tables named as A and B and you want to perform all types of join in Pig.