A struct can also contain a collection of other structs. Since this cannot be done directly in SQL Toql will execute multiple queries and merge the results afterwards.

# #![allow(unused_variables)]
#fn main() {
struct User {
     id: u32,
     name: Option<String>
     #[toql(merge(self="id", other="user_id"))]  // Struct fields for Rust comparison
     mobile_phones : Vec<Phone>
}

struct Phone {
    number: Option<String>
    user_id : Option<u32>
}
#}

Selecting all fields from above with ** will run 2 SELECT statements and merge the resulting Vec<Phone> into Vec<User> by the common value of user.id and phone.user_id.

To merge on composite fields use the attribute multiple times #[toql(merge(..), merge(..)).