In for loop, separating the variables in if condition is not the

way to compare the conditions (If comma separated only the last
specified condition gets executed). This is not desirable, because
terator it can point to results from MessageTableIndex queries and
 jt can point to resultss from ObjectTable and their dimensionality
 is not same and this can result in crash.
Closes-Bug:#1675598

Change-Id: I8af6ef7166900ea4705715fd317d2655d2c3b984

src/query_engine/set_operation.cc

@@ -15,7 +15,7 @@ bool query_result_unit_t::operator<(const query_result_unit_t& rhs) const
     {
         GenDb::DbDataValueVec::const_iterator it = info.begin();
         GenDb::DbDataValueVec::const_iterator jt = rhs.info.begin();
-        for (; it != info.end(), jt != rhs.info.end(); it++, jt++) {
+        for (; it != info.end() && jt != rhs.info.end(); it++, jt++) {
             if (*it < *jt) {
                 return true;
             } else if (*jt < *it) {