[fix](function) support return JsonType for If function

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/If.java

@@ -36,6 +36,7 @@
 import org.apache.doris.nereids.types.FloatType;
 import org.apache.doris.nereids.types.HllType;
 import org.apache.doris.nereids.types.IntegerType;
+import org.apache.doris.nereids.types.JsonType;
 import org.apache.doris.nereids.types.LargeIntType;
 import org.apache.doris.nereids.types.MapType;
 import org.apache.doris.nereids.types.NullType;
@@ -101,7 +102,9 @@ public class If extends ScalarFunction
             FunctionSignature.ret(VarcharType.SYSTEM_DEFAULT)
                     .args(BooleanType.INSTANCE, VarcharType.SYSTEM_DEFAULT, VarcharType.SYSTEM_DEFAULT),
             FunctionSignature.ret(StringType.INSTANCE)
-                    .args(BooleanType.INSTANCE, StringType.INSTANCE, StringType.INSTANCE)
+                    .args(BooleanType.INSTANCE, StringType.INSTANCE, StringType.INSTANCE),
+            FunctionSignature.ret(JsonType.INSTANCE)
+                    .args(BooleanType.INSTANCE, JsonType.INSTANCE, JsonType.INSTANCE)
     );
 
     /**

regression-test/data/query_p0/sql_functions/conditional_functions/test_if_json.out

@@ -0,0 +1,29 @@
+-- This file is automatically generated. You should know what you did if you want to edit this
+-- !if_json_parse --
+1	{"k":"k1","v":"v1"}	{"k":"k1","v":"v1"}
+2	{"k":"k2","v":"v3"}	{"k":"k2","v":"v3"}
+3	\N	\N
+4	{"k":"k4","v":"v4"}	{"k":"k4","v":"v4"}
+5	\N	{"k":"k5","v":"v5"}
+
+-- !case_json_parse --
+1	{"k":"k1","v":"v1"}	{"k":"k1","v":"v1"}
+2	{"k":"k2","v":"v3"}	{"k":"k2","v":"v3"}
+3	\N	\N
+4	{"k":"k4","v":"v4"}	{"k":"k4","v":"v4"}
+5	\N	{"k":"k5","v":"v5"}
+
+-- !case_json_parse_error_to_null --
+1	{"k":"k1","v":"v1"}	{"k":"k1","v":"v1"}
+2	{"k":"k2","v":"v3"}	{"k":"k2","v":"v3"}
+3	\N	\N
+4	{"k":"k4","v":"v4"}	{"k":"k4","v":"v4"}
+5	\N	{"k":"k5","v":"v5"}
+
+-- !case_json_parse_error_to_value --
+1	{"k":"k1","v":"v1"}	{"k":"k1","v":"v1"}
+2	{"k":"k2","v":"v3"}	{"k":"k2","v":"v3"}
+3	\N	\N
+4	{"k":"k4","v":"v4"}	{"k":"k4","v":"v4"}
+5	\N	{"k":"k5","v":"v5"}
+

regression-test/suites/query_p0/sql_functions/conditional_functions/test_if_json.groovy

@@ -0,0 +1,74 @@
+// 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.
+
+suite("test_if_json") {
+    def tblName = "test_if_json"
+    sql """DROP TABLE IF EXISTS ${tblName};"""
+    sql """
+        CREATE TABLE ${tblName} (
+            `id` INT NULL,
+            `v_key` CHAR NULL,
+            `v_json` JSON NULL
+        ) ENGINE=OLAP
+        DUPLICATE KEY(`id`, `v_key`)
+        COMMENT 'OLAP'
+        DISTRIBUTED BY HASH(`id`) BUCKETS 10
+        PROPERTIES (
+        "replication_num" = "1"
+        )
+    """
+
+    sql """ insert into ${tblName} values (1, 'a', '{"k":"k1","v":"v1"}')"""
+    sql """ insert into ${tblName} values (2, 'a', '{"k":"k2","v":"v3"}')"""
+    sql """ insert into ${tblName} values (3, 'b', '{"k":"k3","v":"v3"}')"""
+    sql """ insert into ${tblName} values (4, 'a', '{"k":"k4","v":"v4"}')"""
+    sql """ insert into ${tblName} values (5, 'c', '{"k":"k5","v":"v5"}')"""
+
+    qt_if_json_parse """
+    SELECT id,
+        if(v_key = 'a', JSON_PARSE(v_json), NULL) AS a,
+        if(v_key = 'b', NULL, JSON_PARSE(v_json)) AS b
+    FROM ${tblName}
+    ORDER BY id
+    """
+
+    qt_case_json_parse """
+    SELECT id,
+        CASE v_key WHEN 'a' THEN JSON_PARSE(v_json) ELSE NULL END AS a,
+        CASE v_key WHEN 'b' THEN NULL ELSE JSON_PARSE(v_json) END AS b
+    FROM ${tblName}
+    ORDER BY id
+    """
+
+    qt_case_json_parse_error_to_null """ 
+    SELECT id,
+        CASE v_key WHEN 'a' THEN json_parse_error_to_null(v_json) ELSE NULL END AS a,
+        CASE v_key WHEN 'b' THEN NULL ELSE json_parse_error_to_null(v_json) END AS b
+    FROM ${tblName}
+    ORDER BY id
+    """
+
+    qt_case_json_parse_error_to_value """ 
+    SELECT id,
+        CASE v_key WHEN 'a' THEN json_parse_error_to_value(v_json,json_object()) ELSE NULL END AS a,
+        CASE v_key WHEN 'b' THEN NULL ELSE json_parse_error_to_value(v_json,json_object()) END AS b
+    FROM ${tblName}
+    ORDER BY id
+    """
+
+    sql """DROP TABLE IF EXISTS ${tblName};"""
+}