title: Loopback 4, querying with SQLQuery with postgres connector
body: <p>This is how I have defined my repository following very generic example given at loopback documentation:-</p>
  
  <pre><code>import {DefaultCrudRepository, juggler} from '@loopback/repository';
  import {AModel} from '../models';
  import {TimeseriesDataSource} from '../datasources';
  import {inject} from '@loopback/core';
  
  export class AModelRepository extends DefaultCrudRepository&lt;
    AModel,
    typeof AModel.prototype.id
  &gt; {
    constructor(
      @inject('datasources.timeseries') dataSource: TimeseriesDataSource,
    ) {
      super(AModel, dataSource);
    }
  }
  </code></pre>
  
  <p>I was hoping that if do <code>AModelRepository.execute(sql, null, cb)</code> it would work. But its giving error - <code>Error: Not implemented</code></p>
  
  <p>Any help is highly appreciated.</p>