[fix](window_function) window function first_value/last_value should …

…be always nullable
mrhhsg · Oct 27, 2023 · e690b4f · e690b4f
1 parent bac5239
commit e690b4f
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Showing 4 changed files with 18 additions and 3 deletions.
diff --git a/fe/fe-core/src/main/java/org/apache/doris/catalog/AggregateFunction.java b/fe/fe-core/src/main/java/org/apache/doris/catalog/AggregateFunction.java
@@ -58,7 +58,8 @@ public class AggregateFunction extends Function {
             FunctionSet.ARRAY_AGG, FunctionSet.COLLECT_LIST, FunctionSet.COLLECT_SET);
 
     public static ImmutableSet<String> ALWAYS_NULLABLE_AGGREGATE_FUNCTION_NAME_SET =
-            ImmutableSet.of("stddev_samp", "variance_samp", "var_samp", "percentile_approx");
+            ImmutableSet.of("stddev_samp", "variance_samp", "var_samp", "percentile_approx", "first_value",
+                    "last_value");
 
     public static ImmutableSet<String> CUSTOM_AGGREGATE_FUNCTION_NAME_SET =
             ImmutableSet.of("group_concat");

diff --git a/...in/java/org/apache/doris/nereids/trees/expressions/functions/window/FirstOrLastValue.java b/...in/java/org/apache/doris/nereids/trees/expressions/functions/window/FirstOrLastValue.java
@@ -19,8 +19,8 @@
 
 import org.apache.doris.catalog.FunctionSignature;
 import org.apache.doris.nereids.trees.expressions.Expression;
+import org.apache.doris.nereids.trees.expressions.functions.AlwaysNullable;
 import org.apache.doris.nereids.trees.expressions.functions.ExplicitlyCastableSignature;
-import org.apache.doris.nereids.trees.expressions.functions.PropagateNullable;
 import org.apache.doris.nereids.trees.expressions.shape.UnaryExpression;
 import org.apache.doris.nereids.types.coercion.AnyDataType;
 
@@ -30,7 +30,7 @@
 
 /** parent class for first_value() and last_value() */
 public abstract class FirstOrLastValue extends WindowFunction
-        implements UnaryExpression, PropagateNullable, ExplicitlyCastableSignature {
+        implements UnaryExpression, AlwaysNullable, ExplicitlyCastableSignature {
 
     private static final List<FunctionSignature> SIGNATURES = ImmutableList.of(
             FunctionSignature.retArgType(0).args(AnyDataType.INSTANCE_WITHOUT_INDEX)

diff --git a/regression-test/data/correctness_p0/test_first_value_window.out b/regression-test/data/correctness_p0/test_first_value_window.out
@@ -13,3 +13,10 @@
 23	04-23-10	["p7", "year4"]	["p7", "year4"]
 24	02-24-10-21	[""]	[""]
 
+-- !select_always_nullable --
+21	04-21-11	["amory", "clever"]	\N	\N
+22	04-22-10-21	["doris", "aws", "greate"]	\N	\N
+22	04-22-10-21	["is ", "cute", "tea"]	1	999
+23	04-23-10	["p7", "year4"]	\N	\N
+24	02-24-10-21	[""]	\N	\N
+
diff --git a/regression-test/suites/correctness_p0/test_first_value_window.groovy b/regression-test/suites/correctness_p0/test_first_value_window.groovy
@@ -74,4 +74,11 @@ suite("test_first_value_window") {
 
     qt_select_default """ select *,first_value(state) over(partition by myday order by time_col range between current row and unbounded following) from ${tableName1} order by myday, time_col; """
 
+    qt_select_always_nullable """
+        select
+            *,
+            first_value(1) over(partition by myday order by time_col rows  between 1 preceding and 1 preceding) first_value,
+            last_value(999) over(partition by myday order by time_col rows  between 1 preceding and 1 preceding) last_value
+        from test_first_value_window_array order by myday, time_col;
+    """
 }