From 8734c8152416a7e974ce18da1e80cbb7ce2bed29 Mon Sep 17 00:00:00 2001
From: xiedeyantu <czjourney@163.com>
Date: Sat, 4 Apr 2026 00:16:32 +0800
Subject: [PATCH] Add test cases for SetOpToFilterRule to verify that PROJECT
 containing non-deterministic expressions and subqueries are not merged

---
 .../apache/calcite/test/RelOptRulesTest.java  | 26 ++++++++++
 .../apache/calcite/test/RelOptRulesTest.xml   | 52 +++++++++++++++++++
 2 files changed, 78 insertions(+)

diff --git a/core/src/test/java/org/apache/calcite/test/RelOptRulesTest.java b/core/src/test/java/org/apache/calcite/test/RelOptRulesTest.java
index 1009d3688e1..bd983836d21 100644
--- a/core/src/test/java/org/apache/calcite/test/RelOptRulesTest.java
+++ b/core/src/test/java/org/apache/calcite/test/RelOptRulesTest.java
@@ -11395,6 +11395,32 @@ private void checkLoptOptimizeJoinRule(LoptOptimizeJoinRule rule) {
         .check();
   }
 
+  // If the PROJECT clause contains non-deterministic expressions,
+  // they will not be merged.
+  @Test void testUnionToFilterRuleWithNonDeterministicProject() {
+    final String sql = "SELECT mgr, comm, rand() FROM emp WHERE mgr = 12\n"
+        + "UNION\n"
+        + "SELECT mgr, comm, rand() FROM emp WHERE comm = 5\n";
+    sql(sql)
+        .withPreRule(CoreRules.PROJECT_FILTER_TRANSPOSE)
+        .withRule(CoreRules.UNION_FILTER_TO_FILTER)
+        .checkUnchanged();
+  }
+
+  // If the projection contains a subquery, merging will not be performed.
+  @Test void testUnionToFilterRuleWithSubqueryProject() {
+    final String sql = "SELECT 1, (SELECT COUNT(*) FROM dept)\n"
+        + "FROM emp WHERE mgr = 12\n"
+        + "UNION\n"
+        + "SELECT 1, (SELECT COUNT(*) FROM dept)\n"
+        + "FROM emp WHERE comm = 5\n";
+
+    sql(sql)
+        .withPreRule(CoreRules.PROJECT_FILTER_TRANSPOSE)
+        .withRule(CoreRules.UNION_FILTER_TO_FILTER)
+        .checkUnchanged();
+  }
+
   /** Test case of
    * <a href="https://issues.apache.org/jira/browse/CALCITE-7002">[CALCITE-7002]
    * Create an optimization rule to eliminate UNION
diff --git a/core/src/test/resources/org/apache/calcite/test/RelOptRulesTest.xml b/core/src/test/resources/org/apache/calcite/test/RelOptRulesTest.xml
index f04ced869df..ece2ad5258a 100644
--- a/core/src/test/resources/org/apache/calcite/test/RelOptRulesTest.xml
+++ b/core/src/test/resources/org/apache/calcite/test/RelOptRulesTest.xml
@@ -21495,6 +21495,27 @@ LogicalUnion(all=[false])
   LogicalFilter(condition=[SEARCH($0, Sarg[5, 10])])
     LogicalProject(DEPTNO=[$0])
       LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
+]]>
+    </Resource>
+  </TestCase>
+  <TestCase name="testUnionToFilterRuleWithNonDeterministicProject">
+    <Resource name="sql">
+      <![CDATA[SELECT mgr, comm, rand() FROM emp WHERE mgr = 12
+UNION
+SELECT mgr, comm, rand() FROM emp WHERE comm = 5
+]]>
+    </Resource>
+    <Resource name="planBefore">
+      <![CDATA[
+LogicalUnion(all=[false])
+  LogicalProject(MGR=[$0], COMM=[$1], EXPR$2=[RAND()])
+    LogicalFilter(condition=[=($0, 12)])
+      LogicalProject(MGR=[$3], COMM=[$6])
+        LogicalTableScan(table=[[CATALOG, SALES, EMP]])
+  LogicalProject(MGR=[$0], COMM=[$1], EXPR$2=[RAND()])
+    LogicalFilter(condition=[=($1, 5)])
+      LogicalProject(MGR=[$3], COMM=[$6])
+        LogicalTableScan(table=[[CATALOG, SALES, EMP]])
 ]]>
     </Resource>
   </TestCase>
@@ -21520,6 +21541,37 @@ LogicalUnion(all=[false])
 LogicalAggregate(group=[{0, 1}])
   LogicalProject(MGR=[$3], COMM=[$6])
     LogicalTableScan(table=[[CATALOG, SALES, EMP]])
+]]>
+    </Resource>
+  </TestCase>
+  <TestCase name="testUnionToFilterRuleWithSubqueryProject">
+    <Resource name="sql">
+      <![CDATA[SELECT 1, (SELECT COUNT(*) FROM dept)
+FROM emp WHERE mgr = 12
+UNION
+SELECT 1, (SELECT COUNT(*) FROM dept)
+FROM emp WHERE comm = 5
+]]>
+    </Resource>
+    <Resource name="planBefore">
+      <![CDATA[
+LogicalUnion(all=[false])
+  LogicalProject(EXPR$0=[1], EXPR$1=[$SCALAR_QUERY({
+LogicalAggregate(group=[{}], EXPR$0=[COUNT()])
+  LogicalProject($f0=[0])
+    LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
+})])
+    LogicalFilter(condition=[=($0, 12)])
+      LogicalProject(MGR=[$3])
+        LogicalTableScan(table=[[CATALOG, SALES, EMP]])
+  LogicalProject(EXPR$0=[1], EXPR$1=[$SCALAR_QUERY({
+LogicalAggregate(group=[{}], EXPR$0=[COUNT()])
+  LogicalProject($f0=[0])
+    LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
+})])
+    LogicalFilter(condition=[=($0, 5)])
+      LogicalProject(COMM=[$6])
+        LogicalTableScan(table=[[CATALOG, SALES, EMP]])
 ]]>
     </Resource>
   </TestCase>