When working with dynamic SQL queries, there may be instances when you need to process a result set row by row. SQL cursors come in handy in such scenarios as they allow you to iterate through the result set and perform specific operations on each row.

Here, we will discuss how to use SQL cursors in dynamic SQL queries using an example.

Example Scenario

Let’s assume we have a database table called employee with the following columns: employee_id, first_name, last_name, and salary.

We want to create a dynamic SQL query that retrieves all employee names and salaries and prints them one by one.

Steps to Use SQL Cursors in Dynamic SQL Queries

1. Declare variables and a cursor:

DECLARE @emp_id INT, @emp_name VARCHAR(100), @emp_salary FLOAT;
DECLARE cur CURSOR STATIC FOR
    -- Your dynamic SQL query here
;

1. Open and fetch data from the cursor:

OPEN cur;
FETCH NEXT FROM cur INTO @emp_id, @emp_name, @emp_salary;

1. Process each row using a loop:

WHILE @@FETCH_STATUS = 0
BEGIN
    PRINT 'Employee ID: ' + CONVERT(VARCHAR, @emp_id) + ' | Employee Name: ' + @emp_name + ' | Salary: ' + CONVERT(VARCHAR, @emp_salary);
    FETCH NEXT FROM cur INTO @emp_id, @emp_name, @emp_salary;
END;

1. Close and deallocate the cursor

CLOSE cur;
DEALLOCATE cur;

Putting it All Together

Here’s an example of how the complete code might look like:

DECLARE @emp_id INT, @emp_name VARCHAR(100), @emp_salary FLOAT;
DECLARE cur CURSOR STATIC FOR
    -- Your dynamic SQL query here
    EXEC('SELECT employee_id, first_name + ' ' + last_name as full_name, salary FROM employee');

OPEN cur;
FETCH NEXT FROM cur INTO @emp_id, @emp_name, @emp_salary;

WHILE @@FETCH_STATUS = 0
BEGIN
    PRINT 'Employee ID: ' + CONVERT(VARCHAR, @emp_id) + ' | Employee Name: ' + @emp_name + ' | Salary: ' + CONVERT(VARCHAR, @emp_salary);
    FETCH NEXT FROM cur INTO @emp_id, @emp_name, @emp_salary;
END;

CLOSE cur;
DEALLOCATE cur;

Conclusion

SQL cursors play a vital role in processing result sets row by row, especially when using dynamic SQL queries. By following the steps outlined above, you can effectively use SQL cursors to iterate through a result set and perform operations on each row dynamically.

#SQL #SQLCursors #DynamicSQL