Apache Hive is a data warehouse system for Hadoop that allows users to query and analyze large datasets stored in Hadoop Distributed File System (HDFS). Hive provides a variety of built-in functions that allow users to perform various data manipulation tasks, such as filtering, aggregation, and transformation. Here’s an overview of the different types of functions in Hive:
- Aggregate Functions:
Aggregate functions in Hive allow users to perform calculations on a group of rows and return a single result. Some examples of aggregate functions in Hive are SUM, AVG, MIN, MAX, COUNT, GROUP_CONCAT, etc.
- Math Functions:
Math functions in Hive perform mathematical operations on numeric data types. Some examples of math functions in Hive are ABS, CEIL, FLOOR, ROUND, EXP, LOG, POW, SQRT, etc.
- String Functions:
String functions in Hive perform operations on string data types. Some examples of string functions in Hive are CONCAT, SUBSTR, UPPER, LOWER, TRIM, LENGTH, REPLACE, REGEXP_REPLACE, etc.
- Date and Time Functions:
Date and time functions in Hive perform operations on date and time data types. Some examples of date and time functions in Hive are YEAR, MONTH, DAY, HOUR, MINUTE, SECOND, UNIX_TIMESTAMP, FROM_UNIXTIME, DATEDIFF, DATE_ADD, DATE_SUB, etc.
- Conditional Functions:
Conditional functions in Hive allow users to perform conditional operations based on the values of input data. Some examples of conditional functions in Hive are IF, CASE, COALESCE, NULLIF, NVL, DECODE, etc.
- Collection Functions:
Collection functions in Hive perform operations on complex data types, such as arrays and maps. Some examples of collection functions in Hive are ARRAY, MAP, STRUCT, GET_JSON_OBJECT, JSON_TUPLE, etc.
These are just a few examples of the functions available in Hive. Hive provides a wide range of functions that allow users to perform various data manipulation tasks. The complete list of functions in Hive is available in the official Hive documentation.