code: function createClause (options) {
    options = options || {}
    if (!options.where) return ''
  
    // AST parsing requires a complete SQL.
    const whereTree = parser.parse('SELECT * WHERE ' + options.where).where
    return traverse(whereTree, options)
  }
docs: Creates a viable SQL where clause from a passed in SQL (from a url "where" param)
  @param  {string} options winnow options
  @return {string}         SQL where clause