[fix](join) Preserve input nullability for ASOF match conditions

fe/fe-core/src/main/java/org/apache/doris/nereids/rules/rewrite/AdjustNullable.java

@@ -194,9 +194,11 @@ public Plan visitLogicalJoin(LogicalJoin<? extends Plan, ? extends Plan> join, M
         //    then later at rewrite phase, the join conditions may push down, and the push down condition with proper
         //    nullable attribute.
         // 2) when at the end of rewrite phase, update other conjuncts with join output nullables.
-        //    Just change it to be consistent with BE.
+        //    Just change it to be consistent with BE. ASOF match conditions are evaluated on child input blocks before
+        //    outer-join null padding, so they keep the child nullable attributes in both phases.
         Optional<List<Expression>> otherConjuncts = Optional.empty();
-        if (isAnalyzedPhase) {
+        boolean useJoinOutputNullableForOtherConjuncts = !isAnalyzedPhase && !join.getJoinType().isAsofJoin();
+        if (!useJoinOutputNullableForOtherConjuncts) {
             otherConjuncts = doUpdateExpressions(join.getOtherJoinConjuncts(), replaceMap, false);
         }
         for (Slot slot : join.getOutput()) {
@@ -205,7 +207,7 @@ public Plan visitLogicalJoin(LogicalJoin<? extends Plan, ? extends Plan> join, M
         if (!hadUpdatedMarkConjuncts) {
             markConjuncts = doUpdateExpressions(join.getMarkJoinConjuncts(), replaceMap, false);
         }
-        if (!isAnalyzedPhase) {
+        if (useJoinOutputNullableForOtherConjuncts) {
             otherConjuncts = doUpdateExpressions(join.getOtherJoinConjuncts(), replaceMap, false);
         }
         if (!hashConjuncts.isPresent() && !markConjuncts.isPresent() && !otherConjuncts.isPresent()) {

fe/fe-core/src/test/java/org/apache/doris/nereids/rules/rewrite/AdjustNullableTest.java

@@ -0,0 +1,68 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package org.apache.doris.nereids.rules.rewrite;
+
+import org.apache.doris.nereids.trees.expressions.EqualTo;
+import org.apache.doris.nereids.trees.expressions.Expression;
+import org.apache.doris.nereids.trees.expressions.GreaterThan;
+import org.apache.doris.nereids.trees.expressions.SlotReference;
+import org.apache.doris.nereids.trees.plans.JoinType;
+import org.apache.doris.nereids.trees.plans.logical.LogicalJoin;
+import org.apache.doris.nereids.trees.plans.logical.LogicalOlapScan;
+import org.apache.doris.nereids.util.LogicalPlanBuilder;
+import org.apache.doris.nereids.util.PlanConstructor;
+
+import com.google.common.collect.ImmutableList;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.util.HashMap;
+
+class AdjustNullableTest {
+
+    @Test
+    void testAsofMatchConditionUsesChildNullability() {
+        assertOtherConjunctNullability(JoinType.ASOF_LEFT_INNER_JOIN, false);
+        assertOtherConjunctNullability(JoinType.ASOF_RIGHT_INNER_JOIN, false);
+        assertOtherConjunctNullability(JoinType.ASOF_LEFT_OUTER_JOIN, false);
+        assertOtherConjunctNullability(JoinType.ASOF_RIGHT_OUTER_JOIN, false);
+    }
+
+    @Test
+    void testRegularOuterJoinOtherConditionUsesJoinOutputNullability() {
+        assertOtherConjunctNullability(JoinType.LEFT_OUTER_JOIN, true);
+    }
+
+    private void assertOtherConjunctNullability(JoinType joinType, boolean rightNullable) {
+        LogicalOlapScan left = new LogicalOlapScan(PlanConstructor.getNextRelationId(), PlanConstructor.student,
+                ImmutableList.of(""));
+        LogicalOlapScan right = new LogicalOlapScan(PlanConstructor.getNextRelationId(), PlanConstructor.student,
+                ImmutableList.of(""));
+        Expression hashCondition = new EqualTo(left.getOutput().get(0), right.getOutput().get(0));
+        Expression matchCondition = new GreaterThan(left.getOutput().get(1), right.getOutput().get(1));
+        LogicalJoin<?, ?> join = (LogicalJoin<?, ?>) new LogicalPlanBuilder(left)
+                .join(right, joinType, ImmutableList.of(hashCondition), ImmutableList.of(matchCondition))
+                .build();
+
+        LogicalJoin<?, ?> adjustedJoin = AdjustNullable.doVisitLogicalJoin(join, new HashMap<>(), false, false);
+        GreaterThan adjustedCondition = (GreaterThan) adjustedJoin.getOtherJoinConjuncts().get(0);
+
+        Assertions.assertFalse(((SlotReference) adjustedCondition.left()).nullable());
+        Assertions.assertEquals(rightNullable, ((SlotReference) adjustedCondition.right()).nullable());
+    }
+}