code: function closeWhereContext (select) {
      // only operate if in where context
      if (select.context !== 'where') {
          return
      }
      // debug
      debug('closeWhereContext', select.contextData)
      // get where options
      var column = select.contextData.column
      var not = select.contextData.not
      var operator = select.contextData.operator
      var value = select.contextData.value
      // require column
      if (!column) {
          // if query already has where then nothing in context to add
          if (select.query.where) {
              return
          }
          // otherwise where was created without any columns
          else {
              throwError('column required', select)
          }
      }
      // require value if operator is not null/boolean
      if (operator !== null && operator !== true && operator !== false && value === undefined) {
          throwError('value required', select)
      }
      // make sure query has where property
      if (!select.query.where) {
          select.query.where = {}
      }
      // clause is negated
      if (not) {
          // null/boolean operator
          if (operator === null || operator === true || operator === false) {
              select.query.where[column] = {not: operator}
          }
          // match operator
          else {
              select.query.where[column] = { not: {} }
              select.query.where[column]['not'][operator] = value
          }
      }
      // regular clause
      else {
          // null/boolean operator
          if (operator === null || operator === true || operator === false) {
              select.query.where[column] = operator
          }
          // match operator
          else {
              select.query.where[column] = {}
              select.query.where[column][operator] = value
          }
      }
      // reset contextData
      select.contextData = {}
  }
docs: @function closeWhereContext
  
  create where condition from where context
  
  @param {object} select
  
  @throws {Error}