Authentic Asian Sweet & Sour Sauce - Recipe
You're only going to get an approximate answer to this because there isn't "one sauce" that is sweet and sour, even in Vancouver.  Instead, there are multiple sauces that fit that description, having both acid and sugar in them.  Common ingredients include any of white sugar, brown sugar, honey, vinegar (of several kinds), soy sauce, lemon juice, plum puree, ginger, ketchup, various sour fruits, and spices.

This blog has multiple recipes for sweet-and-sour sauces from Sichuan, which might suit what you're looking for.