From a0b20e561cf5b2fb16e76953f9714c1d53d2f33a Mon Sep 17 00:00:00 2001
From: Igor Gaponenko <gapon@slac.stanford.edu>
Date: Thu, 15 Jun 2023 00:50:52 -0700
Subject: [PATCH] Fixed a bug in the SQL library

---
 src/sql/SqlResults.cc | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/sql/SqlResults.cc b/src/sql/SqlResults.cc
index baa6eccb27..c2cd8e8b0c 100644
--- a/src/sql/SqlResults.cc
+++ b/src/sql/SqlResults.cc
@@ -183,7 +183,12 @@ bool SqlResults::extractFirstValue(std::string& ret, SqlErrorObject& errObj) {
     if (!row) {
         return errObj.addErrMsg("Expecting one row, found no rows");
     }
-    ret = (row[0]);
+    auto ptr = row[0];
+    if (!ptr) {
+        freeResults();
+        return errObj.addErrMsg("NULL returned by the query");
+    }
+    ret = ptr;
     freeResults();
     return true;
 }