Dynamic SQL in SQL Server - A Beginner's Introduction


Dynamic SQL is a powerful feature in SQL Server that allows you to build and execute SQL statements dynamically at runtime. In this beginner's introduction, we'll explore what dynamic SQL is, when to use it, and how to create and execute dynamic SQL statements using SQL code examples.


What is Dynamic SQL?

Dynamic SQL refers to SQL statements that are constructed, modified, or generated as strings during runtime, and then executed. This enables you to create flexible and customizable queries based on various conditions or user input.


Why Use Dynamic SQL?

Dynamic SQL is valuable in situations where you need to:


  • Build queries based on user input or application conditions.
  • Create dynamic reports or pivot tables.
  • Change table or column names dynamically.
  • Execute different operations based on runtime conditions.

Creating Dynamic SQL

Dynamic SQL is typically constructed as a string and then executed using the 

sp_executesql
system stored procedure. Here's a simple example of dynamic SQL to retrieve data based on a condition:


DECLARE @sql NVARCHAR(MAX);
DECLARE @param INT = 100;
SET @sql = N'SELECT * FROM YourTable WHERE YourColumn = @ParamValue';
EXEC sp_executesql @sql, N'@ParamValue INT', @ParamValue = @param;

Using Parameters

It's important to use parameters in dynamic SQL to prevent SQL injection and improve query performance. Parameters can be included in the dynamic SQL string and defined in the 

sp_executesql
call.


What's Next?

You've been introduced to the concept of dynamic SQL in SQL Server as a beginner. To become proficient, you can explore more advanced topics like dynamic column and table names, conditional dynamic queries, and best practices for secure dynamic SQL.


Dynamic SQL is a versatile tool for building flexible and adaptive SQL statements in SQL Server databases.