private String getColumnPath(ASTNode node, TableName tableName, Map<String, String> partitionSpec) {
    // if this ast has only one child, then no column name specified.
    if (node.getChildCount() == 1) {
      return null;
    }

    // Second child node could be partitionSpec or column
    if (node.getChildCount() > 1) {
      ASTNode columnNode = (partitionSpec == null) ? (ASTNode) node.getChild(1) : (ASTNode) node.getChild(2);
      if (columnNode != null) {
        return String.join(".", tableName.getNotEmptyDbTable(), DDLUtils.getFQName(columnNode));
      }
    }

    return null;
  }
Get the column path.
Return column name if exists, column could be DOT separated.
Example: lintString.$elem$.myint.
Return table name for column name if no column has been specified.
ql/src/java/org/apache/hadoop/hive/ql/ddl/table/info/desc/DescTableAnalyzer.java