From bb36de52a68b125b2e181332731f769cf6829b63 Mon Sep 17 00:00:00 2001
From: lichaoyong <lichaoyong158@gmail.com>
Date: Sun, 29 Nov 2020 10:38:30 +0800
Subject: [PATCH] [Bug] Fix locate bug when start_pos larger than str len
 (#4975)

```
select locate('', 'abc', 10);
```
Return 0 not 10
---
 be/src/exprs/string_functions.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/be/src/exprs/string_functions.cpp b/be/src/exprs/string_functions.cpp
index a2b7123f87d477..262e7f0bb7f666 100644
--- a/be/src/exprs/string_functions.cpp
+++ b/be/src/exprs/string_functions.cpp
@@ -480,10 +480,15 @@ IntVal StringFunctions::locate_pos(FunctionContext* context, const StringVal& su
         return IntVal::null();
     }
     if (substr.len == 0) {
-        if (str.len == 0 && start_pos.val > 1) {
+        if (start_pos.val <= 0) {
             return IntVal(0);
+        } else if (start_pos.val == 1) {
+            return IntVal(1);
+        } else if (start_pos.val > str.len) {
+            return IntVal(0);
+        } else {
+            return IntVal(start_pos.val);
         }
-        return IntVal(start_pos.val);
     }
     // Hive returns 0 for *start_pos <= 0,
     // but throws an exception for *start_pos > str->len.