Cook the ditalini pasta in a large pot of salted boiling water according to package directions until al dente. Drain and rinse under cold water until cooled. Transfer to a large bowl.
Add the tomatoes, cucumber, bell pepper, red onion, olives, and parsley to the bowl with the pasta.
In a separate bowl, whisk together the mayonnaise, sour cream, vinegar, Dijon, sugar, garlic powder, salt, and pepper until smooth and creamy.
Pour the dressing over the pasta salad and toss gently until everything is evenly coated.
Cover and refrigerate the pasta salad for at least 1 hour to let the flavors meld together.
Give the salad a good stir and taste for seasoning before serving. Adjust salt and pepper if needed. Serve chilled, and enjoy!