Method stripList

core/src/main/java/org/apache/calcite/sql/SqlPivot.java:106–109

(SqlNodeList list)

  }

  static SqlNodeList stripList(SqlNodeList list) {
    return list.stream().map(SqlPivot::strip)
        .collect(SqlNode.toList(list.pos));
  }

  /** Converts a single-element SqlNodeList to its constituent node.
   * For example, "(1)" becomes "1";