diff --git a/data_diff/databases/presto.py b/data_diff/databases/presto.py
index 339f49ec..e6a5b294 100644
--- a/data_diff/databases/presto.py
+++ b/data_diff/databases/presto.py
@@ -126,9 +126,8 @@ def normalize_uuid(self, value: str, coltype: ColType_UUID) -> str:
         return f"TRIM(CAST({value} AS VARCHAR))"
 
     def normalize_timestamp(self, value: str, coltype: TemporalType) -> str:
-        # TODO rounds
         if coltype.rounds:
-            s = f"date_format(cast({value} as timestamp(6)), '%Y-%m-%d %H:%i:%S.%f')"
+            s = f"date_format(cast({value} as timestamp({coltype.precision})), '%Y-%m-%d %H:%i:%S.%f')"
         else:
             s = f"date_format(cast({value} as timestamp(6)), '%Y-%m-%d %H:%i:%S.%f')"
 
diff --git a/data_diff/queries/ast_classes.py b/data_diff/queries/ast_classes.py
index 2df227dc..8e6053a6 100644
--- a/data_diff/queries/ast_classes.py
+++ b/data_diff/queries/ast_classes.py
@@ -515,7 +515,7 @@ def select(self, *exprs, **named_exprs) -> Self | ITable:
         named_exprs = _drop_skips_dict(named_exprs)
         exprs += _named_exprs_as_aliases(named_exprs)
         resolve_names(self.source_table, exprs)
-        # TODO Ensure exprs <= self.columns ?
+        # No explicit subset check needed; resolve_names() raises KeyError for invalid column names (when schema is present)
         return attrs.evolve(self, columns=exprs)