to_unixtime does not support timestamps with a timezone (#14490)

Author: Omega359

datafusion/functions/src/datetime/to_unixtime.rs

@@ -108,9 +108,12 @@ impl ScalarUDFImpl for ToUnixtimeFunc {
             DataType::Int32 | DataType::Int64 | DataType::Null | DataType::Float64 => {
                 args[0].cast_to(&DataType::Int64, None)
             }
-            DataType::Date64 | DataType::Date32 | DataType::Timestamp(_, None) => args[0]
+            DataType::Date64 | DataType::Date32 => args[0]
                 .cast_to(&DataType::Timestamp(TimeUnit::Second, None), None)?
                 .cast_to(&DataType::Int64, None),
+            DataType::Timestamp(_, tz) => args[0]
+                .cast_to(&DataType::Timestamp(TimeUnit::Second, tz), None)?
+                .cast_to(&DataType::Int64, None),
             #[allow(deprecated)] // TODO: migrate to invoke_with_args
             DataType::Utf8 => ToTimestampSecondsFunc::new()
                 .invoke_batch(args, batch_size)?
@@ -120,6 +123,7 @@ impl ScalarUDFImpl for ToUnixtimeFunc {
             }
         }
     }
+
     fn documentation(&self) -> Option<&Documentation> {
         self.doc()
     }

datafusion/sqllogictest/test_files/timestamps.slt

@@ -2872,6 +2872,16 @@ select to_unixtime('2020-09-08T12:00:00+00:00');
 ----
 1599566400
 
+query I
+select to_unixtime(arrow_cast(to_timestamp('2023-01-14T01:01:30'), 'Timestamp(Second, Some("+05:30"))'));
+----
+1673638290
+
+query I
+select to_unixtime(arrow_cast(to_timestamp('2023-01-14T01:01:30'), 'Timestamp(Millisecond, None)'));
+----
+1673658090
+
 query I
 select to_unixtime('01-14-2023 01:01:30+05:30', '%q', '%d-%m-%Y %H/%M/%S', '%+', '%m-%d-%Y %H:%M:%S%#z');
 ----