code: public Column<?> column(String columnName) {
          for (Column<?> column : columns()) {
              String name = column.name().trim();
              if (name.equalsIgnoreCase(columnName)) {
                  return column;
              }
          }
          throw new IllegalStateException(String.format("Column %s does not exist in table %s", columnName, name()));
      }
docs: Returns the column with the given columnName, ignoring case