SQL

In SQL, these ACID properties collectively provide the necessary guarantees to maintain data integrity, consistency, and reliability even in the face of system failures, concurrent access, or errors. Developers and database administrators can configure transactions and isolation levels based on the requirements of their application to balance performance and data integrity EXAMPLE: In this example,…

An index is a database structure that enhances the speed of data retrieval operations on a table. It’s created on one or more columns of a table to speed up SELECT, JOIN, and WHERE queries by allowing the database engine to quickly locate rows that match the indexed values. Benefits of Indexes: Example: CREATE INDEX…

Views: A view is a virtual table created from the result of a SQL query. It doesn’t store data on its own; instead, it presents data from one or more underlying tables in a structured manner. Views allow you to simplify complex queries, control data access, and provide an abstraction layer for users to interact…

Working with NULL values in SQL is an important aspect of handling missing or unknown data in a database. NULL represents the absence of a value and is not the same as an empty string or zero. Understanding how NULL behaves in SQL queries and how to work with it is crucial for accurate data…

Advanced filtering and conditional expressions are powerful features in SQL that allow you to manipulate and filter data based on complex conditions. One commonly used tool for implementing conditional expressions is the CASE statement. Advanced Filtering: Advanced filtering involves creating conditions that go beyond simple comparisons. It often includes logical operators (AND, OR, NOT) and…

FULL JOIN: A FULL JOIN, also known as a FULL OUTER JOIN, combines the results of both the LEFT JOIN and the RIGHT JOIN. It returns all rows from both tables, along with matched rows and unmatched rows from each table. If a row doesn’t have a match in the other table, the missing columns…

COUNT: The COUNT function is used to count the number of rows in a result set that meet a certain condition. It is often used to count the occurrences of a particular value or to retrieve the total number of rows in a table. SELECT COUNT() FROM orders; -- Count all rows in the "orders"…

A subquery, also known as a nested query or inner query, is a query that is embedded within another query. It’s a powerful feature in SQL that allows you to retrieve data from one or more tables based on the results of another query. Subqueries are often used in situations where you need to perform…