public static void replaceTabAlias(Map<String, ExprNodeDesc> exprMap, String oldAlias, String newAlias) {
    if (exprMap != null) {
      ExprNodeDescUtils.replaceTabAlias(exprMap.values(), oldAlias, newAlias);
    }
  }
Checks wether the two expression sets have a common deterministic intersection.
ql/src/java/org/apache/hadoop/hive/ql/plan/ExprNodeDescUtils.java