code: function Builder(client) {
    this.client = client;
    this.and = this;
    this._single = {};
    this._statements = [];
    this._method = 'select';
    if (client.config) {
      saveAsyncStack(this, 5);
      this._debug = client.config.debug;
    }
    // Internal flags used in the builder.
    this._joinFlag = 'inner';
    this._boolFlag = 'and';
    this._notFlag = false;
    this._asColumnFlag = false;
  }
docs: Typically called from `knex.builder`, start a new query building chain.