SQL, or Structured Query Language, is a standard language for dealing with relational databases. It can be used to perform tasks such as update data on a database or retrieve data from a database. This blog post will delve into the intermediates of SQL and also touch on some advanced SQL topics.
SQL is a foundational skill for any data professional. At its core, SQL provides the means for connecting and interacting with databases. Basic SQL commands include SELECT, INSERT, UPDATE, DELETE, and WHERE. These commands allow you to retrieve, add, modify, remove, and filter data, respectively. Understanding these commands and their structure is essential for managing database operations.
Intermediate SQL topics include JOINS, UNIONS, CASE statements, updating and deleting data, PARTITION BY, understanding data types, aliasing, creating views, HAVING and GROUP BY statements and understanding the difference between primary and foreign keys.
Advanced SQL covers complex queries and concepts such as Subqueries, Stored Procedures, Triggers, Common Table Expressions (CTEs), SYS tables, Temp tables, string functions like TRIM, LTRIM, REPLACE, SUBSTRING, UPPER, LOWER, Regular Expressions, and data importing and exporting from and to various file types and sources. Understanding these concepts significantly improves one's data management skills.