fix: Use dynamic timezone in now() function for accurate timestamp

datafusion/functions/src/datetime/now.rs

@@ -80,7 +80,7 @@ impl ScalarUDFImpl for NowFunc {
     fn return_field_from_args(&self, _args: ReturnFieldArgs) -> Result<FieldRef> {
         Ok(Field::new(
             self.name(),
-            Timestamp(Nanosecond, Some("+00:00".into())),
+            Timestamp(Nanosecond, Some("+00".into())),
             false,
         )
         .into())
@@ -106,8 +106,16 @@ impl ScalarUDFImpl for NowFunc {
             .execution_props()
             .query_execution_start_time
             .timestamp_nanos_opt();
+
+        let timezone = info
+            .execution_props()
+            .config_options
+            .as_ref()
+            .map(|opts| opts.execution.time_zone.as_str())
+            .unwrap_or("+00");
+
         Ok(ExprSimplifyResult::Simplified(Expr::Literal(
-            ScalarValue::TimestampNanosecond(now_ts, Some("+00:00".into())),
+            ScalarValue::TimestampNanosecond(now_ts, Some(timezone.into())),
             None,
         )))
     }

datafusion/sqllogictest/test_files/dates.slt

@@ -85,7 +85,7 @@ g
 h
 
 ## Plan error when compare Utf8 and timestamp in where clause
-statement error DataFusion error: type_coercion\ncaused by\nError during planning: Cannot coerce arithmetic expression Timestamp\(Nanosecond, Some\("\+00:00"\)\) \+ Utf8 to valid types
+statement error DataFusion error: type_coercion\ncaused by\nError during planning: Cannot coerce arithmetic expression Timestamp\(Nanosecond, Some\("\+00"\)\) \+ Utf8 to valid types
 select i_item_desc from test
 where d3_date > now() + '5 days';
 

datafusion/sqllogictest/test_files/timestamps.slt

@@ -73,6 +73,16 @@ true
 ##########
 ## Current time Tests
 ##########
+statement ok
+SET TIME ZONE = '+08'
+
+query T
+select arrow_typeof(now());
+----
+Timestamp(Nanosecond, Some("+08"))
+
+statement ok
+SET TIME ZONE = '+00'
 
 query B
 select cast(now() as time) = current_time();