refactor: clean up some code in QueryExt::select_ids

1. There was no need to use `drain` since we own the vector itself and
   not a mutable reference to it, just `for row in rows` would have been
   fine.

2. Rather than creating the second vector and using a loop to push
   transformed values, using `map` is more idiomatic (and efficient in
   this case, too, since the vec was created with `Vec::new` instead of
   `Vec::with_capacity`).

3. The TODO comment seemed outdated, there are no queries to add tracing
   too in this function.

Author: aqrln

query-engine/connectors/sql-query-connector/src/query_ext.rs

@@ -135,16 +135,14 @@ impl<Q: Queryable + ?Sized> QueryExt for Q {
         let field_names: Vec<_> = model_id.fields().map(|field| field.name()).collect();
         let meta = column_metadata::create(field_names.as_slice(), &idents);
 
-        // TODO: Add tracing
-        let mut rows = self.filter(select.into(), &meta, ctx).await?;
-        let mut result = Vec::new();
-
-        for row in rows.drain(0..) {
-            let tuples: Vec<_> = model_id.scalar_fields().zip(row.values.into_iter()).collect();
-            let record_id: SelectionResult = SelectionResult::new(tuples);
-
-            result.push(record_id);
-        }
+        let rows = self.filter(select.into(), &meta, ctx).await?;
+        let result = rows
+            .into_iter()
+            .map(|row| {
+                let tuples = model_id.scalar_fields().zip(row.values.into_iter()).collect();
+                SelectionResult::new(tuples)
+            })
+            .collect();
 
         Ok(result)
     }