From ee3dd423b9ae51a3bcf830c9e7ca5ceba2bd2398 Mon Sep 17 00:00:00 2001
From: Pxl <pxl290@qq.com>
Date: Wed, 28 Sep 2022 08:54:49 +0800
Subject: [PATCH] [Bug](function) core dump on substr #13007

---
 be/src/vec/functions/function_string.h        |  4 ++++
 .../string_functions/test_string_function.out | 21 +++++++++++++++++++
 .../test_string_function.groovy               |  7 +++++++
 3 files changed, 32 insertions(+)

diff --git a/be/src/vec/functions/function_string.h b/be/src/vec/functions/function_string.h
index c6294a08c4..a9834ad2ca 100644
--- a/be/src/vec/functions/function_string.h
+++ b/be/src/vec/functions/function_string.h
@@ -187,6 +187,10 @@ private:
             }
 
             int fixed_pos = start[i];
+            if (fixed_pos < -(int)index.size()) {
+                StringOP::push_empty_string(i, res_chars, res_offsets);
+                continue;
+            }
             if (fixed_pos < 0) {
                 fixed_pos = index.size() + fixed_pos + 1;
             }
diff --git a/regression-test/data/query_p0/sql_functions/string_functions/test_string_function.out b/regression-test/data/query_p0/sql_functions/string_functions/test_string_function.out
index 6bdd10491d..fb1a9c6bed 100644
--- a/regression-test/data/query_p0/sql_functions/string_functions/test_string_function.out
+++ b/regression-test/data/query_p0/sql_functions/string_functions/test_string_function.out
@@ -236,3 +236,24 @@ c1
 -- !sql --
 bc
 
+-- !sql --
+
+
+-- !sql --
+
+
+-- !sql --
+a
+
+-- !sql --
+
+
+-- !sql --
+a
+
+-- !sql --
+
+
+-- !sql --
+
+
diff --git a/regression-test/suites/query_p0/sql_functions/string_functions/test_string_function.groovy b/regression-test/suites/query_p0/sql_functions/string_functions/test_string_function.groovy
index 8feee3e9e3..8ebd486b3d 100644
--- a/regression-test/suites/query_p0/sql_functions/string_functions/test_string_function.groovy
+++ b/regression-test/suites/query_p0/sql_functions/string_functions/test_string_function.groovy
@@ -125,4 +125,11 @@ suite("test_string_function") {
     qt_sql "select substring('abc1', 5);"
     qt_sql "select substring('abc1def', 2, 2);"
 
+    qt_sql "select substr('a',3,1);"
+    qt_sql "select substr('a',2,1);"
+    qt_sql "select substr('a',1,1);"
+    qt_sql "select substr('a',0,1);"
+    qt_sql "select substr('a',-1,1);"
+    qt_sql "select substr('a',-2,1);"
+    qt_sql "select substr('a',-3,1);"
 }