From ba8a410d6d88ebe285197046c9f8dd127795b69b Mon Sep 17 00:00:00 2001
From: Bob Liu <bobliu@taosdata.com>
Date: Sun, 12 Nov 2023 19:15:41 +0800
Subject: [PATCH] fix toISO8601Function

---
 include/common/ttime.h           | 7 +++++++
 source/common/src/ttime.c        | 4 ++++
 source/libs/scalar/src/sclfunc.c | 9 +++++++++
 3 files changed, 20 insertions(+)

diff --git a/include/common/ttime.h b/include/common/ttime.h
index 306b5105d0..1dfa609064 100644
--- a/include/common/ttime.h
+++ b/include/common/ttime.h
@@ -118,6 +118,13 @@ int32_t taosChar2Ts(const char* format, SArray** formats, const char* tsStr, int
 void    TEST_ts2char(const char* format, int64_t ts, int32_t precision, char* out, int32_t outLen);
 int32_t TEST_char2ts(const char* format, int64_t* ts, int32_t precision, const char* tsStr);
 
+/// @brief get offset seconds from zero timezone to input timezone
+///        for +XX timezone, the offset to zero is negative value
+/// @param tzStr timezonestr, eg: +0800, -0830, -08
+/// @param offset seconds, eg: +08 offset -28800, -01 offset 3600
+/// @return 0 success, other fail
+int32_t offsetOfTimezone(char* tzStr, int64_t* offset);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/common/src/ttime.c b/source/common/src/ttime.c
index a701c88a24..385be92774 100644
--- a/source/common/src/ttime.c
+++ b/source/common/src/ttime.c
@@ -194,6 +194,10 @@ int32_t parseTimezone(char* str, int64_t* tzOffset) {
   return 0;
 }
 
+int32_t offsetOfTimezone(char* tzStr, int64_t* offset) {
+  return parseTimezone(tzStr, offset);
+}
+
 /*
  * rfc3339 format:
  * 2013-04-12T15:52:01+08:00
diff --git a/source/libs/scalar/src/sclfunc.c b/source/libs/scalar/src/sclfunc.c
index e7c6297f44..6144ebd340 100644
--- a/source/libs/scalar/src/sclfunc.c
+++ b/source/libs/scalar/src/sclfunc.c
@@ -1083,6 +1083,15 @@ int32_t toISO8601Function(SScalarParam *pInput, int32_t inputNum, SScalarParam *
       memmove(fraction, fraction + TSDB_TIME_PRECISION_SEC_DIGITS, TSDB_TIME_PRECISION_SEC_DIGITS);
     }
 
+    // trans current timezone's unix ts to dest timezone
+    // offset = delta from dest timezone to zero
+    // delta from zero to current timezone = 3600 * (cur)tsTimezone
+    int64_t offset = 0;
+    if (0 != offsetOfTimezone(tz, &offset)) {
+      goto _end;
+    }
+    timeVal -= offset + 3600 * ((int64_t)tsTimezone);
+
     struct tm tmInfo;
     int32_t len = 0;