Rohith
Creator of whiletrue.live.
Conversion Functions in SQL
Functions in SQL enable we to perform feats such as determining the sum of a column or converting all the characters of a string to uppercase.
RDD in Spark
RDD (Resilient Distributed Dataset) in spark is a fundamental data structure of Spark. It is the primary data abstraction in Apache Spark and the Spark Core.
Posted August 31, 2022 by Rohith ‐ 5 min read
⌖ apache spark bigdata distributed-system spark-fundamentals rdd
General Functions in SQL
Functions in SQL enable we to perform feats such as determining the sum of a column or converting all the characters of a string to uppercase.
Joins in SQL
One of the most powerful features of SQL is its capability to gather and manipulate data from across several tables. Without this feature we would have to store all the data elements necessary for each application in one table. Without common tables we would need to store the same data in several tables. Imagine having to redesign, rebuild, and repopulate our tables and databases every time our user needed a query with a new piece of information. The JOIN statement of SQL enables us to design smaller, more specific tables that are easier to maintain than larger tables.
Sub Queries in SQL
A subquery is a query whose results are passed as the argument for another query. Sub queries enable us to bind several queries together.