Adding an Extra Column in SQL SELECT Query with Conditions

Описание: Learn how to enhance your SQL SELECT queries by adding extra columns based on specific conditions. Explore examples and improve your SQL skills.
---
Disclaimer/Disclosure: Some of the content was synthetically produced using various Generative AI (artificial intelligence) tools; so, there may be inaccuracies or misleading information present in the video. Please consider this before relying on the content to make any decisions or take any actions etc. If you still have any concerns, please feel free to write them in a comment. Thank you.
---
Adding an Extra Column in SQL SELECT Query with Conditions

Structured Query Language (SQL) is a powerful tool for managing and retrieving data from relational databases. One common requirement in data analysis is to add an extra column to the result set based on certain conditions. In this guide, we will explore how to achieve this using the CASE statement in SQL.

The CASE Statement

The CASE statement in SQL allows you to perform conditional logic within a query. It is particularly useful when you want to add a new column with values determined by specified conditions.

The basic syntax for a simple CASE statement is as follows:

[[See Video to Reveal this Text or Code Snippet]]

Here, newColumnName is the name you want to give to the new column, and it will contain values based on the specified conditions.

Let's walk through some examples to illustrate how to use the CASE statement effectively.

Example 1: Categorizing Data

Suppose you have a table employees with a column salary, and you want to categorize employees into different salary ranges. You can use a CASE statement to create a new column salary_category:

[[See Video to Reveal this Text or Code Snippet]]

In this example, the salary_category column will contain values like 'Low', 'Medium', or 'High' based on the employee's salary.

Example 2: Conditional Formatting

Suppose you have a table orders with a column order_date, and you want to create a new column order_status based on whether an order was placed in the last 30 days:

[[See Video to Reveal this Text or Code Snippet]]

Here, the order_status column will indicate whether an order is recent or old based on the specified condition.

Example 3: Combining Conditions

You can also combine multiple conditions within a CASE statement. Suppose you want to create a column product_status in a table products based on both the stock_quantity and sales columns:

[[See Video to Reveal this Text or Code Snippet]]

In this example, the product_status column will provide information about the product's stock and sales status.

Conclusion

Adding extra columns to your SQL SELECT queries based on conditions is a valuable skill for data analysis. The CASE statement allows you to introduce flexibility and customization to your result sets. Experiment with different conditions and scenarios to enhance your SQL queries and gain deeper insights into your data.