address comments

Author: chelsea-lin

bigframes/core/compile/sqlglot/aggregations/unary_compiler.py

@@ -16,6 +16,7 @@
 
 import typing
 
+import pandas as pd
 import sqlglot.expressions as sge
 
 from bigframes import dtypes
@@ -82,6 +83,9 @@ def _(
     expr = column.expr
     if column.dtype == dtypes.BOOL_DTYPE:
         expr = sge.Cast(this=column.expr, to="INT64")
-    # Will be null if all inputs are null. Pandas defaults to zero sum though.
+
     expr = apply_window_if_present(sge.func("SUM", expr), window)
-    return sge.func("IFNULL", expr, ir._literal(0, column.dtype))
+
+    # Will be null if all inputs are null. Pandas defaults to zero sum though.
+    zero = pd.to_timedelta(0) if column.dtype == dtypes.TIMEDELTA_DTYPE else 0
+    return sge.func("IFNULL", expr, ir._literal(zero, column.dtype))

bigframes/core/utils.py

@@ -234,7 +234,7 @@ def wrapper(*args, **kwargs):
 
 
 def timedelta_to_micros(
-    timedelta: typing.Union[pd.Timedelta, datetime.timedelta, np.timedelta64, int]
+    timedelta: typing.Union[pd.Timedelta, datetime.timedelta, np.timedelta64]
 ) -> int:
     if isinstance(timedelta, pd.Timedelta):
         # pd.Timedelta.value returns total nanoseconds.
@@ -248,7 +248,4 @@ def timedelta_to_micros(
             (timedelta.days * 3600 * 24) + timedelta.seconds
         ) * 1_000_000 + timedelta.microseconds
 
-    if isinstance(timedelta, int):
-        return timedelta
-
     raise TypeError(f"Unrecognized input type: {type(timedelta)}")