[fix](nereids) Interval.equals() should consider timeUnit (#59316)

Author: englefly

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/literal/Interval.java

@@ -79,6 +79,11 @@ public String toDigest() {
         return sb.toString();
     }
 
+    @Override
+    protected boolean extraEquals(Expression that) {
+        return that instanceof Interval && this.timeUnit().equals(((Interval) that).timeUnit());
+    }
+
     /**
      * Supported time unit.
      */

fe/fe-core/src/test/java/org/apache/doris/nereids/trees/expressions/literal/IntervalTest.java

@@ -0,0 +1,32 @@
+// 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.trees.expressions.literal;
+
+import org.apache.doris.nereids.trees.expressions.literal.Interval.TimeUnit;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class IntervalTest {
+    @Test
+    public void testIntervalEquals() {
+        Interval i1 = new Interval(new IntegerLiteral(1), TimeUnit.DAY);
+        Interval i2 = new Interval(new IntegerLiteral(1), TimeUnit.SECOND);
+        Assertions.assertNotEquals(i1, i2);
+    }
+}