fix(cubesql): Support explicit UTC as timezone in pushdown SQL generation

rust/cubesql/cubesql/src/compile/engine/df/wrapper.rs

@@ -1706,26 +1706,37 @@
                             }
                         }
                         // ScalarValue::Date64(_) => {}
-                        ScalarValue::TimestampSecond(s, _) => {
+
+                        // generate_sql_for_timestamp will call Utc constructors, so only support UTC zone for now
+                        // DataFusion can return "UTC" for stuff like `NOW()` during constant folding
+                        ScalarValue::TimestampSecond(s, tz)
+                            if matches!(tz.as_deref(), None | Some("UTC")) =>
+                        {
                             generate_sql_for_timestamp!(s, timestamp, sql_generator, sql_query)
                         }
-                        ScalarValue::TimestampMillisecond(ms, None) => {
+                        ScalarValue::TimestampMillisecond(ms, tz)
+                            if matches!(tz.as_deref(), None | Some("UTC")) =>
+                        {
                             generate_sql_for_timestamp!(
                                 ms,
                                 timestamp_millis_opt,
                                 sql_generator,
                                 sql_query
                             )
                         }
-                        ScalarValue::TimestampMicrosecond(ms, None) => {
+                        ScalarValue::TimestampMicrosecond(ms, tz)
+                            if matches!(tz.as_deref(), None | Some("UTC")) =>
+                        {
                             generate_sql_for_timestamp!(
                                 ms,
                                 timestamp_micros,
                                 sql_generator,
                                 sql_query
                             )
                         }
-                        ScalarValue::TimestampNanosecond(nanoseconds, None) => {
+                        ScalarValue::TimestampNanosecond(nanoseconds, tz)
+                            if matches!(tz.as_deref(), None | Some("UTC")) =>
+                        {
                             generate_sql_for_timestamp!(
                                 nanoseconds,
                                 timestamp_nanos,

rust/cubesql/cubesql/src/compile/test/test_wrapper.rs

@@ -541,6 +541,184 @@ async fn test_simple_subquery_wrapper_filter_and_projection() {
     let _physical_plan = query_plan.as_physical_plan().await.unwrap();
 }
 
+// TODO add more time zones
+// TODO add more TS syntax variants
+// TODO add TIMESTAMPTZ variant
+/// Using TIMESTAMP WITH TIME ZONE with actual timezone in wrapper should render proper timestamptz in SQL
+#[tokio::test]
+async fn test_wrapper_timestamptz() {
+    if !Rewriter::sql_push_down_enabled() {
+        return;
+    }
+    init_testing_logger();
+
+    let query_plan = convert_select_to_query_plan(
+        // language=PostgreSQL
+        r#"
+SELECT
+    customer_gender
+FROM KibanaSampleDataEcommerce
+WHERE
+    order_date >= TIMESTAMP WITH TIME ZONE '2024-02-03T04:05:06Z'
+    AND
+--   This filter should trigger pushdown
+    LOWER(customer_gender) = 'male'
+GROUP BY
+    1
+;
+            "#
+        .to_string(),
+        DatabaseProtocol::PostgreSQL,
+    )
+    .await;
+
+    let physical_plan = query_plan.as_physical_plan().await.unwrap();
+    println!(
+        "Physical plan: {}",
+        displayable(physical_plan.as_ref()).indent()
+    );
+
+    assert!(query_plan
+        .as_logical_plan()
+        .find_cube_scan_wrapper()
+        .wrapped_sql
+        .unwrap()
+        .sql
+        .contains(
+            "${KibanaSampleDataEcommerce.order_date} >= timestamptz '2024-02-03T04:05:06.000Z'"
+        ));
+}
+
+// TODO add more time zones
+// TODO add more TS syntax variants
+// TODO add TIMESTAMPTZ variant
+/// Using TIMESTAMP WITH TIME ZONE with actual timezone in ungrouped wrapper should render proper timestamptz in SQL
+#[tokio::test]
+async fn test_wrapper_timestamptz_ungrouped() {
+    if !Rewriter::sql_push_down_enabled() {
+        return;
+    }
+    init_testing_logger();
+
+    let query_plan = convert_select_to_query_plan(
+        // language=PostgreSQL
+        r#"
+SELECT
+    customer_gender
+FROM KibanaSampleDataEcommerce
+WHERE
+    order_date >= TIMESTAMP WITH TIME ZONE '2024-02-03T04:05:06Z'
+    AND
+--   This filter should trigger pushdown
+    LOWER(customer_gender) = 'male'
+;
+            "#
+        .to_string(),
+        DatabaseProtocol::PostgreSQL,
+    )
+    .await;
+
+    let physical_plan = query_plan.as_physical_plan().await.unwrap();
+    println!(
+        "Physical plan: {}",
+        displayable(physical_plan.as_ref()).indent()
+    );
+
+    assert!(query_plan
+        .as_logical_plan()
+        .find_cube_scan_wrapper()
+        .wrapped_sql
+        .unwrap()
+        .sql
+        .contains(
+            "${KibanaSampleDataEcommerce.order_date} >= timestamptz '2024-02-03T04:05:06.000Z'"
+        ));
+}
+
+/// Using NOW() in wrapper should render proper timestamptz in SQL
+#[tokio::test]
+async fn test_wrapper_now() {
+    if !Rewriter::sql_push_down_enabled() {
+        return;
+    }
+    init_testing_logger();
+
+    let query_plan = convert_select_to_query_plan(
+        // language=PostgreSQL
+        r#"
+SELECT
+    customer_gender
+FROM KibanaSampleDataEcommerce
+WHERE
+    order_date >= NOW()
+    AND
+--   This filter should trigger pushdown
+    LOWER(customer_gender) = 'male'
+GROUP BY
+    1
+;
+            "#
+        .to_string(),
+        DatabaseProtocol::PostgreSQL,
+    )
+    .await;
+
+    let physical_plan = query_plan.as_physical_plan().await.unwrap();
+    println!(
+        "Physical plan: {}",
+        displayable(physical_plan.as_ref()).indent()
+    );
+
+    assert!(query_plan
+        .as_logical_plan()
+        .find_cube_scan_wrapper()
+        .wrapped_sql
+        .unwrap()
+        .sql
+        .contains("${KibanaSampleDataEcommerce.order_date} >= timestamptz"));
+}
+
+/// Using NOW() in ungrouped wrapper should render proper timestamptz in SQL
+#[tokio::test]
+async fn test_wrapper_now_ungrouped() {
+    if !Rewriter::sql_push_down_enabled() {
+        return;
+    }
+    init_testing_logger();
+
+    let query_plan = convert_select_to_query_plan(
+        // language=PostgreSQL
+        r#"
+SELECT
+    customer_gender
+FROM KibanaSampleDataEcommerce
+WHERE
+    order_date >= NOW()
+    AND
+--   This filter should trigger pushdown
+    LOWER(customer_gender) = 'male'
+;
+            "#
+        .to_string(),
+        DatabaseProtocol::PostgreSQL,
+    )
+    .await;
+
+    let physical_plan = query_plan.as_physical_plan().await.unwrap();
+    println!(
+        "Physical plan: {}",
+        displayable(physical_plan.as_ref()).indent()
+    );
+
+    assert!(query_plan
+        .as_logical_plan()
+        .find_cube_scan_wrapper()
+        .wrapped_sql
+        .unwrap()
+        .sql
+        .contains("${KibanaSampleDataEcommerce.order_date} >= timestamptz"));
+}
+
 #[tokio::test]
 async fn test_case_wrapper() {
     if !Rewriter::sql_push_down_enabled() {