code: def fetch_sdss_galaxy_colors(
      data_home=None, download_if_missing=True
  ):
      """Loader for SDSS galaxy colors.
  
      This function directly queries the sdss SQL database at
      http://cas.sdss.org/
  
      Parameters
      ----------
      data_home : optional, default=None
          Specify another download and cache folder for the datasets. By default
          all astroML data is stored in '~/astroML_data'.
  
      download_if_missing : optional, default=True
          If False, raise a IOError if the data is not locally available
          instead of trying to download the data from the source site.
  
      Returns
      -------
      data : recarray, shape = (10000,)
          record array containing magnitudes and redshift for each galaxy
      """
      data_home = get_data_home(data_home)
  
      archive_file = os.path.join(data_home, ARCHIVE_FILE)
  
      query_text = "\n".join(
          (
              "SELECT TOP %i" % NOBJECTS,
              "  p.u, p.g, p.r, p.i, p.z, s.class, s.z, s.zerr",
              "FROM PhotoObj AS p",
              "  JOIN SpecObj AS s ON s.bestobjid = p.objid",
              "WHERE ",
              "  p.u BETWEEN 0 AND 19.6",
              "  AND p.g BETWEEN 0 AND 20",
              "  AND s.class <> 'UNKNOWN'",
              "  AND s.class <> 'STAR'",
              "  AND s.class <> 'SKY'",
              "  AND s.class <> 'STAR_LATE'",
          )
      )
  
      if not os.path.exists(archive_file):
          if not download_if_missing:
              raise IOError(
                  "data not present on disk. "
                  "set download_if_missing=True to download"
              )
  
          print("querying for %i objects" % NOBJECTS)
          print(query_text)
          output = sql_query(query_text)
          print("finished.")
  
          kwargs = {
              "delimiter": ",",
              "skip_header": 2,
              "names": GAL_COLORS_NAMES,
              "dtype": None,
              "encoding": "ascii",
          }
  
          data = np.genfromtxt(output, **kwargs)
          np.save(archive_file, data)
  
      else:
          data = np.load(archive_file)
  
      return data
  
imports: import os
  import numpy
  from .None import get_data_home
  from .tools import sql_query
label_desc: Use image node_id 1 for calling a global function with example usage: fetch_sdss_galaxy_colors(data_home, download_if_missing) and returns: data