int tblvar=infer_tablevar_from_colref(qs->mvars[cv],fta_tree->fm,schema);
if(tblvar<0){
fprintf(stderr,"ERROR, Merge column %d (%s) was not found in any of the tables.\n",cv,qs->mvars[cv]->to_string().c_str());
int tblvar=infer_tablevar_from_colref(qs->mvars[cv],fta_tree->fm,schema);
if(tblvar<0){
fprintf(stderr,"ERROR, Merge column %d (%s) was not found in any of the tables.\n",cv,qs->mvars[cv]->to_string().c_str());