How to Convert Your SQL Query to LINQ with Ease

Discover how to convert SQL queries to `LINQ` expressions in C-. This guide walks you through the process step-by-step with practical examples.
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How to convert this sql query into linq query

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Convert Your SQL Query to LINQ with Ease

If you’re venturing into the world of data querying and you've previously worked with SQL, you might find yourself needing to convert SQL queries into LINQ for your C- applications, especially in ASP.NET Core projects. This can often be tricky if you're not familiar with the nuances of LINQ. Today we're going to tackle a specific example which illustrates this conversion process in a clear and structured manner.

The Problem: SQL Query Conversion

Suppose you have a SQL query that counts the number of client burnout statuses and categorizes them as 'Pending', 'Approved', or 'Denied'. Here’s how your SQL query looks:

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

This query works perfectly in SQL, but converting it into a LINQ expression can be confusing.

The Solution: Converting SQL to LINQ

Here’s how you can transform your SQL query into a LINQ expression using C-. The trick lies in using a switch expression to replace the SQL CASE statement. Let's break it down step by step.

1. Understand Your Data Model

Before writing the LINQ query, ensure you have an understanding of your data model. You will be querying a collection named Client_BurnOuts. Each object will have a Status property that corresponds to an integer value.

2. Grouping the Data

In the SQL query, we're grouping by Status. In LINQ, this can be done using the group by clause.

3. The Switch Expression

Replace the SQL CASE statement with a switch expression in C-. This is where you categorize the Status.

4. The Full LINQ Query

Finally, the complete LINQ query would look like this:

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

Explanation of the LINQ Query Components:

from o in Client_BurnOuts: This part is choosing the data from the Client_BurnOuts collection.

group o by o.Status into g: This groups the data by the Status provided in each Client_BurnOut.

select new: This creates a new anonymous object where we define the Status and the totalCount.

switch expression: This cleverly replaces the SQL CASE statement and will categorize the results accordingly.

g.Count(): This counts how many entries fall within each grouped category.

Conclusion

Converting SQL queries to LINQ can seem daunting at first, but with a structured approach, you can create clean and efficient queries in C-. Remember to understand your data model and leverage expressions that mimic SQL functionality effectively.

By following these steps, you’ll become adept at transitioning between these two powerful querying languages. Happy coding!