From 5b2cdc469090fe20660c70b54f105a03fbc351f0 Mon Sep 17 00:00:00 2001
From: LiBinfeng <1204975323@qq.com>
Date: Wed, 16 Aug 2023 10:56:17 +0800
Subject: [PATCH] [Fix](Planner) fix case function with null cast to array null

---
 .../src/main/java/org/apache/doris/analysis/CastExpr.java   | 2 +-
 .../sql_functions/case_function/test_case_function_null.out | 3 +++
 .../case_function/test_case_function_null.groovy            | 6 +++++-
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/analysis/CastExpr.java b/fe/fe-core/src/main/java/org/apache/doris/analysis/CastExpr.java
index 6ceb8e3d84c760d..cb78d785395d30a 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/analysis/CastExpr.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/analysis/CastExpr.java
@@ -314,7 +314,7 @@ public void analyze() throws AnalysisException {
         // it is necessary to check if it is castable before creating fn.
         // char type will fail in canCastTo, so for compatibility, only the cast of array type is checked here.
         if (type.isArrayType() || childType.isArrayType()) {
-            if (childType.isNull() || !Type.canCastTo(childType, type)) {
+            if (!Type.canCastTo(childType, type)) {
                 throw new AnalysisException("Invalid type cast of " + getChild(0).toSql()
                         + " from " + childType + " to " + type);
             }
diff --git a/regression-test/data/query_p0/sql_functions/case_function/test_case_function_null.out b/regression-test/data/query_p0/sql_functions/case_function/test_case_function_null.out
index de51eb0306ad099..2d2816c012eb392 100644
--- a/regression-test/data/query_p0/sql_functions/case_function/test_case_function_null.out
+++ b/regression-test/data/query_p0/sql_functions/case_function/test_case_function_null.out
@@ -16,3 +16,6 @@
 -- !sql_case2 --
 -2
 
+-- !sql_case3 --
+0
+
diff --git a/regression-test/suites/query_p0/sql_functions/case_function/test_case_function_null.groovy b/regression-test/suites/query_p0/sql_functions/case_function/test_case_function_null.groovy
index 63e67a40f009fb9..269a0bf0db87cff 100644
--- a/regression-test/suites/query_p0/sql_functions/case_function/test_case_function_null.groovy
+++ b/regression-test/suites/query_p0/sql_functions/case_function/test_case_function_null.groovy
@@ -228,4 +228,8 @@ suite("test_case_function_null", "query,p0") {
             END)
         FROM case_null2;
     """
-}
\ No newline at end of file
+
+
+    qt_sql_case3 """SELECT COUNT(CASE (NOT (NOT true))  WHEN (((- 47960023)) IS NOT NULL) THEN NULL ELSE NULL END) from case_null1;"""
+
+}