long numRows = stats.getNumRows();
if (child instanceof ExprNodeGenericFuncDesc) {
ExprNodeGenericFuncDesc genFunc = (ExprNodeGenericFuncDesc) child;
GenericUDF udf = genFunc.getGenericUDF();
if (udf instanceof GenericUDFOPEqual ||
udf instanceof GenericUDFOPEqualNS) {
String colName = null;
String tabAlias = null;