feat(cubesql): Support NULLIF in projection

Author: MazterQyou

rust/cubesql/cubesql/src/compile/mod.rs

@@ -16103,4 +16103,44 @@ ORDER BY \"COUNT(count)\" DESC"
             }
         )
     }
+
+    #[tokio::test]
+    async fn test_thoughtspot_nullif_measure_dimension() {
+        init_logger();
+
+        let logical_plan = convert_select_to_query_plan(
+            r#"
+            SELECT
+                NULLIF(CAST("ta_1"."taxful_total_price" AS FLOAT8), 0.0) "ca_1",
+                NULLIF(CAST("ta_1"."count" AS FLOAT8), 0.0) "ca_2"
+            FROM KibanaSampleDataEcommerce "ta_1"
+            GROUP BY
+                "ca_1",
+                "ca_2"
+            ORDER BY
+                "ca_1" ASC,
+                "ca_2" ASC
+            "#
+            .to_string(),
+            DatabaseProtocol::PostgreSQL,
+        )
+        .await
+        .as_logical_plan();
+
+        assert_eq!(
+            logical_plan.find_cube_scan().request,
+            V1LoadRequestQuery {
+                measures: Some(vec!["KibanaSampleDataEcommerce.count".to_string()]),
+                dimensions: Some(vec![
+                    "KibanaSampleDataEcommerce.taxful_total_price".to_string()
+                ]),
+                segments: Some(vec![]),
+                time_dimensions: None,
+                order: None,
+                limit: None,
+                offset: None,
+                filters: None,
+            }
+        )
+    }
 }

rust/cubesql/cubesql/src/compile/rewrite/rules/split.rs

@@ -2165,6 +2165,18 @@ impl RewriteRules for SplitRules {
                 ),
                 inner_aggregate_split_replacer("?expr", "?cube"),
             ),
+            // NullIf
+            rewrite(
+                "split-push-down-nullif-inner-replacer",
+                inner_aggregate_split_replacer(
+                    fun_expr(
+                        "NullIf",
+                        vec!["?expr".to_string(), literal_expr("?literal")],
+                    ),
+                    "?cube",
+                ),
+                inner_aggregate_split_replacer("?expr", "?cube"),
+            ),
             // IS NULL, IS NOT NULL
             rewrite(
                 "split-push-down-is-null-inner-replacer",
@@ -3781,6 +3793,34 @@ impl RewriteRules for SplitRules {
             )
             .into_iter(),
         );
+        // NullIf
+        rules.extend(
+            self.outer_aggr_group_expr_aggr_combinator_rewrite(
+                "split-push-down-nullif-replacer",
+                |split_replacer| {
+                    split_replacer(
+                        fun_expr("NullIf", vec!["?expr".to_string(), literal_expr("?else")]),
+                        "?cube",
+                    )
+                },
+                |_| vec![],
+                |split_replacer| {
+                    fun_expr(
+                        "NullIf",
+                        vec![
+                            split_replacer("?expr".to_string(), "?cube"),
+                            literal_expr("?else"),
+                        ],
+                    )
+                },
+                |_, _| true,
+                false,
+                true,
+                true,
+                Some(vec![("?expr", column_expr("?column"))]),
+            )
+            .into_iter(),
+        );
         // IS NULL
         rules.extend(
             self.outer_aggr_group_expr_aggr_combinator_rewrite(