From b8452812dffbf39104ca1f1c5053dc9951dfa23a Mon Sep 17 00:00:00 2001
From: zhangstar333 <87313068+zhangstar333@users.noreply.github.com>
Date: Mon, 23 Oct 2023 15:47:12 +0800
Subject: [PATCH] [bug](function) fix regexp_extract_all can't handle empty str
 (#25717)

---
 be/src/vec/functions/function_regexp.cpp                    | 1 +
 .../string_functions/test_string_function_regexp.out        | 6 ++++++
 .../string_functions/test_string_function_regexp.groovy     | 1 +
 3 files changed, 8 insertions(+)

diff --git a/be/src/vec/functions/function_regexp.cpp b/be/src/vec/functions/function_regexp.cpp
index 1a38fe741e..4da133a6f5 100644
--- a/be/src/vec/functions/function_regexp.cpp
+++ b/be/src/vec/functions/function_regexp.cpp
@@ -361,6 +361,7 @@ struct RegexpExtractAllImpl {
         }
 
         if (res_matches.empty()) {
+            StringOP::push_empty_string(index_now, result_data, result_offset);
             return;
         }
 
diff --git a/regression-test/data/query_p0/sql_functions/string_functions/test_string_function_regexp.out b/regression-test/data/query_p0/sql_functions/string_functions/test_string_function_regexp.out
index 1684a03a15..133076ec13 100644
--- a/regression-test/data/query_p0/sql_functions/string_functions/test_string_function_regexp.out
+++ b/regression-test/data/query_p0/sql_functions/string_functions/test_string_function_regexp.out
@@ -67,6 +67,12 @@ d
 -- !sql --
 ['ab','c','c','c']
 
+-- !sql_regexp_extract_all --
+	0
+	0
+	0
+	0
+
 -- !sql --
 a-b-c
 
diff --git a/regression-test/suites/query_p0/sql_functions/string_functions/test_string_function_regexp.groovy b/regression-test/suites/query_p0/sql_functions/string_functions/test_string_function_regexp.groovy
index e3e04a5456..59414f5c1b 100644
--- a/regression-test/suites/query_p0/sql_functions/string_functions/test_string_function_regexp.groovy
+++ b/regression-test/suites/query_p0/sql_functions/string_functions/test_string_function_regexp.groovy
@@ -58,6 +58,7 @@ suite("test_string_function_regexp") {
     qt_sql "select regexp_extract_all('xxfs','f');"
     qt_sql "select regexp_extract_all('asdfg', '(z|x|c|)');"
     qt_sql "select regexp_extract_all('abcdfesscca', '(ab|c|)');"
+    qt_sql_regexp_extract_all "select regexp_extract_all('', '\"([^\"]+)\":'), length(regexp_extract_all('', '\"([^\"]+)\":')) from test_string_function_regexp;"
 
     qt_sql "SELECT regexp_replace('a b c', \" \", \"-\");"
     qt_sql "SELECT regexp_replace('a b c','(b)','<\\\\1>');"