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In today's data-driven world, stored procedures can be crucial for the efficient handling and processing of database operations. As a DBA or developer, there may be instances where you need to write a stored procedure with dynamic SQL. In this blog post, we will be focusing on how to create DB2 Stored Procedures with Dynamic SQL, utilizing technologies from SQL Server 2016, SQL Server 2017, MySQL 5.7, DB2 11.1, and Azure SQL.

Dynamic SQL is a programming technique that enables you to build SQL statements dynamically at runtime. You can create more general-purpose, flexible applications by using dynamic SQL because the full text of a SQL statement may be unknown at compilation. For instance, you may need to select data from a table, but you don't know the table's name until runtime. Dynamic SQL handles such scenarios with ease.

To create a Stored Procedure with Dynamic SQL in DB2, you need to follow a series of steps. The first step is to define the procedure. Here's an example of how to do it:

CREATE PROCEDURE DYNAMIC_SQL()
LANGUAGE SQL
BEGIN
DECLARE @SQL VARCHAR(100);
SET @SQL = 'SELECT * FROM TABLE_NAME';
PREPARE stmt FROM @SQL;
EXECUTE stmt;
END

In the above DB2 code, we have created a stored procedure named DYNAMIC_SQL. We declared a variable '@SQL' to hold our SQL statement. We then prepared our SQL statement from the '@SQL' variable and finally executed the statement.

Dynamic SQL is not only limited to DB2 but also can be used in SQL Server and MySQL. In SQL Server 2016 and 2017, you can use the EXEC or sp_executesql stored procedure to execute dynamic SQL. For example:

DECLARE @SQL NVARCHAR(500);
SET @SQL = N'SELECT * FROM TABLE_NAME';
EXEC sp_executesql @SQL;

In MySQL 5.7, you can use prepared statements to execute dynamic SQL:

SET @SQL = 'SELECT * FROM TABLE_NAME';
PREPARE stmt FROM @SQL;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

In Azure SQL, similar to SQL Server, you can use the EXEC or sp_executesql stored procedure to execute dynamic SQL. It's also important to note that Azure SQL fully supports the use of dynamic SQL in stored procedures, functions, and triggers.

Dynamic SQL brings flexibility to your applications, enabling you to create more generic and reusable SQL Statements. However, it's important to be cautious when using it, as it opens up potential for SQL Injection attacks. Always ensure to validate and sanitize your inputs when constructing a dynamic SQL.