Make the brine by brining the water to a boil, and adding the salt and sugar, mixing to combine until they dissolve and then off the heat adding the vinegar and the oil.
Pour the brine over the vegetables and let it stand for about 15-20 minutes. The vegetables will wilt slightly. Place the salad into glass canning jars or even into a large bowl or bowls. Make sure that the vegetables are covered completely with the brine.
Store in the refrigerator. Marinate for 24-48 hours before serving.
Recipe by Olga's Flavor Factory at https://www.olgasflavorfactory.com/recipes/marinated-assorted-vegetable-salad/