From 4d3db821bbc37f5c60290b385e57a2b033e903e1 Mon Sep 17 00:00:00 2001
From: Amos Bird <amosbird@gmail.com>
Date: Sat, 21 Aug 2021 17:03:16 +0800
Subject: [PATCH] Fix JSONExtract String with null value.

---
 src/Functions/FunctionsJSON.h                                   | 2 ++
 .../queries/0_stateless/01915_json_extract_raw_string.reference | 1 +
 tests/queries/0_stateless/01915_json_extract_raw_string.sql     | 2 ++
 3 files changed, 5 insertions(+)

diff --git a/src/Functions/FunctionsJSON.h b/src/Functions/FunctionsJSON.h
index d0762ff9a8d..0ac04ae0dec 100644
--- a/src/Functions/FunctionsJSON.h
+++ b/src/Functions/FunctionsJSON.h
@@ -695,6 +695,8 @@ struct JSONExtractTree
         {
             if (element.isString())
                 return JSONExtractStringImpl<JSONParser>::insertResultToColumn(dest, element, {});
+            else if (element.isNull())
+                return false;
             else
                 return JSONExtractRawImpl<JSONParser>::insertResultToColumn(dest, element, {});
         }
diff --git a/tests/queries/0_stateless/01915_json_extract_raw_string.reference b/tests/queries/0_stateless/01915_json_extract_raw_string.reference
index 839cb33f5f2..3a41f35710c 100644
--- a/tests/queries/0_stateless/01915_json_extract_raw_string.reference
+++ b/tests/queries/0_stateless/01915_json_extract_raw_string.reference
@@ -1 +1,2 @@
 ('123','456','[7,8,9]')
+\N
diff --git a/tests/queries/0_stateless/01915_json_extract_raw_string.sql b/tests/queries/0_stateless/01915_json_extract_raw_string.sql
index 6ba94ac6dfd..4c5be79f6ef 100644
--- a/tests/queries/0_stateless/01915_json_extract_raw_string.sql
+++ b/tests/queries/0_stateless/01915_json_extract_raw_string.sql
@@ -1 +1,3 @@
 select JSONExtract('{"a": "123", "b": 456, "c": [7, 8, 9]}', 'Tuple(a String, b String, c String)');
+
+with '{"string_value":null}' as json select JSONExtract(json, 'string_value', 'Nullable(String)');