[Fix](nereids) fix rule SimplifyWindowExpression

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

@@ -27,10 +27,12 @@
 import org.apache.doris.nereids.trees.expressions.Slot;
 import org.apache.doris.nereids.trees.expressions.WindowExpression;
 import org.apache.doris.nereids.trees.expressions.functions.BoundFunction;
+import org.apache.doris.nereids.trees.expressions.functions.agg.Count;
 import org.apache.doris.nereids.trees.expressions.literal.TinyIntLiteral;
 import org.apache.doris.nereids.trees.plans.Plan;
 import org.apache.doris.nereids.trees.plans.logical.LogicalProject;
 import org.apache.doris.nereids.trees.plans.logical.LogicalWindow;
+import org.apache.doris.nereids.util.TypeCoercionUtils;
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
@@ -87,11 +89,13 @@ private Plan simplify(MatchingContext<LogicalWindow<Plan>> ctx) {
             if (function instanceof BoundFunction) {
                 BoundFunction boundFunction = (BoundFunction) function;
                 String name = ((BoundFunction) function).getName();
-                if ((name.equals(COUNT) && boundFunction.child(0).notNullable())
+                if ((name.equals(COUNT) && checkCount((Count) boundFunction))
                         || REWRRITE_TO_CONST_WINDOW_FUNCTIONS.contains(name)) {
                     projectionsBuilder.add(new Alias(alias.getExprId(), new TinyIntLiteral((byte) 1), alias.getName()));
                 } else if (REWRRITE_TO_SLOT_WINDOW_FUNCTIONS.contains(name)) {
-                    projectionsBuilder.add(new Alias(alias.getExprId(), boundFunction.child(0), alias.getName()));
+                    projectionsBuilder.add(new Alias(alias.getExprId(),
+                            TypeCoercionUtils.castIfNotSameType(boundFunction.child(0), boundFunction.getDataType()),
+                            alias.getName()));
                 } else {
                     remainWindowExpression.add(expr);
                 }
@@ -120,4 +124,8 @@ private Plan simplify(MatchingContext<LogicalWindow<Plan>> ctx) {
                     window.child(0)));
         }
     }
+
+    private boolean checkCount(Count count) {
+        return count.isCountStar() || count.child(0).notNullable();
+    }
 }

regression-test/data/nereids_rules_p0/simplify_window_expression/simplify_window_expression.out

@@ -119,28 +119,28 @@
 -- !select_avg --
 \N	\N	\N
 \N	\N	\N
-1	1	1
-1	1	1
-2	2	2
-3	3	3
-3	3	3
-4	4	4
-5	5	5
-5	5	5
-7	7	7
+1	1.0	1.0
+1	1.0	1.0
+2	2.0	2.0
+3	3.0	3.0
+3	3.0	3.0
+4	4.0	4.0
+5	5.0	5.0
+5	5.0	5.0
+7	7.0	7.0
 
 -- !more_than_pk --
 \N	\N	\N
 \N	\N	\N
-1	1	1
-1	1	1
-2	2	2
-3	3	3
-3	3	3
-4	4	4
-5	5	5
-5	5	5
-7	7	7
+1	1.0	1.0
+1	1.0	1.0
+2	2.0	2.0
+3	3.0	3.0
+3	3.0	3.0
+4	4.0	4.0
+5	5.0	5.0
+5	5.0	5.0
+7	7.0	7.0
 
 -- !select_last_value_shape --
 PhysicalResultSink
@@ -163,18 +163,31 @@ PhysicalResultSink
 ------filter((mal_test_simplify_window.__DORIS_DELETE_SIGN__ = 0))
 --------PhysicalOlapScan[mal_test_simplify_window]
 
+-- !select_count_star_col1 --
+\N	1	1
+1	1	1
+1	1	1
+2	1	1
+2	1	1
+2	1	1
+3	1	1
+3	1	1
+4	1	1
+6	1	1
+6	1	1
+
 -- !select_upper_plan_use_all_rewrite --
 \N	\N
 \N	\N
-1	1
-1	1
-2	2
-3	3
-3	3
-4	4
-5	5
-5	5
-7	7
+1	1.0
+1	1.0
+2	2.0
+3	3.0
+3	3.0
+4	4.0
+5	5.0
+5	5.0
+7	7.0
 
 -- !select_upper_plan_use_rewrite_and_not_rewrite --
 \N	\N	\N

regression-test/suites/nereids_rules_p0/simplify_window_expression/simplify_window_expression.groovy

@@ -78,6 +78,9 @@ suite("simplify_window_expression") {
         explain shape plan
         select b, avg(b) over (partition by a,b,c) c1, avg(b) over (partition by a,b,c order by b) c2
         from mal_test_simplify_window"""
+    qt_select_count_star_col1 """
+        select a,count() over (partition by a,b) c1, count() over (partition by a,b order by a) c2
+        from mal_test_simplify_window order by 1,2,3;"""
 
     qt_select_upper_plan_use_all_rewrite """
         select b, c1 from (select b,avg(b) over (partition by a,b) c1