public NamedJoinInfo getNamedJoinInfo() {
    return namedJoinInfo;
  }
Return a new row resolver that is combination of left RR and right RR.
The schema will be schema of left, schema of right

@param leftRR
@param rightRR
@return
@throws SemanticException
ql/src/java/org/apache/hadoop/hive/ql/parse/RowResolver.java