fix regression cases

Author: mrhhsg

regression-test/data/nereids_p0/json_p0/test_json_load_and_function.out

@@ -780,7 +780,7 @@
 
 -- !select --
 1	\N	\N
-2	null	null
+2	null	\N
 3	true	true
 4	false	false
 5	100	100
@@ -881,7 +881,7 @@
 13	[]	\N
 14	[123,456]	123
 15	["abc","def"]	abc
-16	[null,true,false,100,6.18,"abc"]	null
+16	[null,true,false,100,6.18,"abc"]	\N
 17	[{"k1":"v41","k2":400},1,"a",3.14]	{"k1":"v41","k2":400}
 18	{"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]}	{"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]}
 26	\N	\N

regression-test/data/nereids_p0/json_p0/test_json_load_unique_key_and_function.out

@@ -619,7 +619,7 @@
 
 -- !select --
 1	\N	\N
-2	null	null
+2	null	\N
 3	true	true
 4	false	false
 5	100	100
@@ -702,7 +702,7 @@
 13	[]	\N
 14	[123,456]	123
 15	["abc","def"]	abc
-16	[null,true,false,100,6.18,"abc"]	null
+16	[null,true,false,100,6.18,"abc"]	\N
 17	[{"k1":"v41","k2":400},1,"a",3.14]	{"k1":"v41","k2":400}
 18	{"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]}	{"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]}
 26	\N	\N

regression-test/data/nereids_p0/jsonb_p0/test_jsonb_load_and_function.out

@@ -925,7 +925,7 @@
 
 -- !jsonb_extract_string_select --
 1	\N	\N
-2	null	null
+2	null	\N
 3	true	true
 4	false	false
 5	100	100
@@ -1026,7 +1026,7 @@
 13	[]	\N
 14	[123,456]	123
 15	["abc","def"]	abc
-16	[null,true,false,100,6.18,"abc"]	null
+16	[null,true,false,100,6.18,"abc"]	\N
 17	[{"k1":"v41","k2":400},1,"a",3.14]	{"k1":"v41","k2":400}
 18	{"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]}	{"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]}
 26	\N	\N

regression-test/data/nereids_p0/jsonb_p0/test_jsonb_load_unique_key_and_function.out

@@ -734,7 +734,7 @@
 
 -- !jsonb_extract_string_select --
 1	\N	\N
-2	null	null
+2	null	\N
 3	true	true
 4	false	false
 5	100	100
@@ -817,7 +817,7 @@
 13	[]	\N
 14	[123,456]	123
 15	["abc","def"]	abc
-16	[null,true,false,100,6.18,"abc"]	null
+16	[null,true,false,100,6.18,"abc"]	\N
 17	[{"k1":"v41","k2":400},1,"a",3.14]	{"k1":"v41","k2":400}
 18	{"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]}	{"k1":"v31","k2":300,"a1":[{"k1":"v41","k2":400},1,"a",3.14]}
 26	\N	\N

regression-test/suites/query_p0/sql_functions/json_functions/test_json_extract.groovy

@@ -20,7 +20,7 @@ suite("test_json_extract") {
     qt_sql_string2 """ SELECT JSON_EXTRACT_STRING(null, '\$.k1'); """
     qt_sql_string3 """ SELECT JSON_EXTRACT_STRING('{"k1":"v31","k2":300}', NULL); """
     qt_sql_string4 """ SELECT JSON_EXTRACT_STRING('{"k1":"v31","k2":{"sub_key": 1234.56}}', '\$.k2.sub_key'); """
-    qt_sql_string5 """ SELECT JSON_EXTRACT_STRING(json_array("abc", 123, STR_TO_DATE('2025-06-05 14:47:01', '%Y-%m-%d %H:%i:%s')), '\$.[2]'); """
+    qt_sql_string5 """ SELECT JSON_EXTRACT_STRING(json_array("abc", 123, STR_TO_DATE('2025-06-05 14:47:01', '%Y-%m-%d %H:%i:%s')), '\$[2]'); """
     qt_sql_string6 """ SELECT JSON_EXTRACT_STRING('{"k1":"v31","k2": null}', '\$.k2'); """
     qt_sql_string7 """ SELECT JSON_EXTRACT_STRING('{"k1":"v31","k2":300}', '\$.k3'); """