store resolved field name in index

Author: oleggator

datafusion/common/src/dfschema.rs

@@ -620,16 +620,18 @@ impl DFSchema {
 
 fn build_index(fields: &[DFField]) -> BTreeMap<OwnedFieldReference, Vec<usize>> {
     let mut index = BTreeMap::new();
-    let iter = fields
-        .iter()
-        .map(|field| {
-            OwnedFieldReference::new(
-                field.name().clone(),
-                field.qualifier().map(|q| q.to_owned_reference()),
-            )
-        })
-        .enumerate();
-    for (idx, field) in iter {
+    for (idx, df_field) in fields.iter().enumerate() {
+        let field = match &df_field.qualifier {
+            Some(q) => OwnedFieldReference::new(
+                df_field.name().clone(),
+                Some(q.to_owned_reference()),
+            ),
+            None => {
+                let column = Column::from_qualified_name(df_field.name());
+                OwnedFieldReference::new(column.name, column.relation)
+            }
+        };
+
         match index.entry(field) {
             Entry::Vacant(entry) => {
                 entry.insert(vec![idx]);