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HQL COMMANDS FOR DATA ANALYTICS

Using HQL (Hive Query Language), data analysts can easily manipulate and manage data stored in Apache Hive tables on top of the Hadoop Distributed File System (HDFS). HQL commands are simple yet powerful and allow a wide range of analytics. Here is a list of some of the more commonly used HQL commands for data analytics.

SELECT

The SELECT command allows you to retrieve data from a Hive table. It can be used to select specific columns or all columns in a table. The syntax for this command is:
SELECT [columns] FROM [table name];

WHERE

The WHERE command allows you to filter the results of a query based on certain criteria. This is very useful when you need to retrieve specific data from a table. The syntax for this command is:
SELECT [columns] FROM [table name] WHERE [criteria];

GROUP BY & HAVING CLAUSE

The GROUP BY and HAVING clauses allow you to aggregate your data before it is retrieved. This is extremely useful for creating summary reports and other analysis that require aggregated data. The syntax for this command is:
SELECT [columns] FROM [table name] WHERE [criteria] GROUP BY [columns] HAVING [criteria];

ORDER BY & LIMIT

The ORDER BY and LIMIT clauses allow you to sort the results of a query and limit the number of rows returned, respectively. This is very helpful when you need to display sorted data in a UI or limit the number of rows displayed on a report. The syntax for this command is:
SELECT [columns] FROM [table name] WHERE [criteria] ORDER BY [columns] LIMIT [# of rows];

JOINS

The JOIN command allows you to join two Hive tables together. This is extremely useful for retrieving data from multiple tables with a single query. The syntax for this command is:
SELECT [columns] FROM [table 1] JOIN [table 2] ON [conditions];