Date functions
Darshini
SQL provides various date functions to manipulate and extract information from date and time values. These functions vary slightly across different databases (MySQL, PostgreSQL, SQL Server, Oracle), but the core…
SQL
Handling NULL in join condition
In SQL, the behavior of joins involving NULL values in the join conditions depends on the type of join used. Here’s a breakdown: 1. INNER JOIN Behavior: Rows with NULL…
REVOKE
The SQL REVOKE command is used to remove or withdraw permissions from users or roles, which were previously granted using the GRANT command. It is an essential tool for managing…
GRANT
The GRANT command in SQL is used to assign permissions to users or roles, enabling them to perform specific operations on database objects. These permissions are essential for managing access…
SELECT
The SQL SELECT command is one of the most fundamental and frequently used operations in relational database management. It retrieves data from one or more tables, enabling you to query…
UPDATE
The SQL UPDATE command is used to modify existing records in a table. It allows developers and database administrators to make changes to one or multiple rows based on specified…
INSERT
The SQL INSERT command is used to add new records to a table. Whether you’re inserting single or multiple rows, data from another table, or computed values, this command is…
Truncate
The TRUNCATE command in SQL is a Data Definition Language (DDL) operation used to remove all rows from a table, effectively resetting it to an empty state. Unlike DELETE, it…
ALTER
The ALTER command in SQL is a powerful tool used to modify the structure of existing database objects like tables, columns, or constraints. This guide explores the types of ALTER…
DROP
The DROP command in SQL is used to delete database objects permanently. This includes tables, databases, indexes, views, or constraints. Once dropped, the object cannot be recovered unless a backup…