Category Archives: sql

SQL – DELETE JOIN Table of content Simple deletion operation in SQL can be performed on a single record or multiple records of a table. And to delete records from multiple tables, the most straightforward approach would be to delete records from one table at a time. However, SQL makes it easier by allowing the […]

SQL – Self Join Table of content Self Join, as its name suggests, is a type of join that combines the records of a table with itself. Suppose an organization, while organizing a Christmas party, is choosing a Secret Santa among its employees based on some colors. It is designed to be done by assigning […]

SQL – IS NOT NULL Table of content A NULL value indicates a missing or unknown value. It appears to be blank and does not contain any data. It is very important to understand that a NULL value is different than a zero value or a field that contains spaces. For checking null values we […]