From 0983c1becf0e66de8b06024e6504f4ffb7dc245a Mon Sep 17 00:00:00 2001
From: Andrew Hutchings <andrew@linuxjedi.co.uk>
Date: Mon, 10 Jun 2019 16:46:24 +0100
Subject: [PATCH] MCOL-2230 Fix TIMEDIFF() handling

TIMEDIFF would not compare datetime with string correctly, causing a
NULL saturation.
---
 utils/funcexp/func_timediff.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/utils/funcexp/func_timediff.cpp b/utils/funcexp/func_timediff.cpp
index 369bb80a1..c4de35a0d 100644
--- a/utils/funcexp/func_timediff.cpp
+++ b/utils/funcexp/func_timediff.cpp
@@ -118,7 +118,10 @@ string Func_timediff::getStrVal(rowgroup::Row& row,
 
         case execplan::CalpontSystemCatalog::TIME:
         case execplan::CalpontSystemCatalog::DATETIME:
-            if (type1 != type2)
+            // Diff between time and datetime returns NULL in MariaDB
+            if ((type2 == execplan::CalpontSystemCatalog::TIME ||
+                 type2 == execplan::CalpontSystemCatalog::DATETIME) &&
+                 type1 != type2)
             {
                 isNull = true;
                 break;