Don't assume nullable if no join syntax is known

sqlparser/lib/src/analysis/types/resolving_visitor.dart

@@ -711,16 +711,17 @@ class TypeResolver extends RecursiveVisitor<TypeExpectation, void> {
     } else if (column is DelegatedColumn && column.innerColumn != null) {
       _handleColumn(column.innerColumn);
 
+      var makeNullable = false;
+
       if (column is AvailableColumn) {
         // The nullability depends on whether the column was introduced in an
         // outer join.
         final model = context != null ? JoinModel.of(context) : null;
-        final isNullable =
-            model == null || model.availableColumnIsNullable(column);
-        _lazyCopy(column, column.innerColumn, makeNullable: isNullable);
-      } else {
-        _lazyCopy(column, column.innerColumn);
+
+        makeNullable = model != null && model.availableColumnIsNullable(column);
       }
+
+      _lazyCopy(column, column.innerColumn, makeNullable: makeNullable);
     }
   }
 

sqlparser/test/analysis/types2/resolver_test.dart

@@ -308,4 +308,29 @@ WITH RECURSIVE
     expect(session.typeOf(columns[2]),
         const ResolvedType(type: BasicType.int, nullable: true));
   });
+
+  test('analyzes nested columns', () {
+    engine.registerTableFromSql('''
+      CREATE TABLE x (
+        id INTEGER NOT NULL,
+        other INTEGER
+      );
+    ''');
+
+    final resolver = obtainResolver('''
+      SELECT xxx.id FROM (
+        SELECT * FROM (
+          SELECT id FROM x
+        ) xx
+      ) xxx;
+    ''');
+
+    final session = resolver.session;
+    final stmt = resolver.session.context.root as SelectStatement;
+    final columns = stmt.resolvedColumns!;
+
+    expect(columns, hasLength(1));
+    expect(session.typeOf(columns[0]),
+        const ResolvedType(type: BasicType.int, nullable: false));
+  });
 }