Can you "add" more results with Advaced Syntax?

Sometimes we want to make a search result showing some specific products. We then use that url for our newsletters.

I know you can subtract with advanced syntax, but it doesn’t seem like you are able to add.

Example:
I want to do a search that only outputs two specific products by using the SKU’s as a search term.
I can search “34636” and it will only show that product. - is there a way to add more products to the result by typing something like “34636” + “54363”?

You’re correct that you can’t add records via advanced syntax. They would either need to be included via the query or added using Algolia Rules

If you’re doing programmatically, you may be able to achieve this result using a query filter:

// Only "LG" or "Samsung" smartphones
index.search('smartphone', {
  filters: 'sku: 34636 OR sku: 54363'
}).then(({ hits }) => {
  console.log(hits);
});