How do I return only selected fields from the model and its relation

Questions and Answers
7

Actually, you can retrieve images by using withRelated, but .columns() seems to have no effect here on the morph relationship. As it returns all of the columns in any case.

withRelated: {
        images: qb => { //includes images relations
          qb.columns('url'); //doesn't return only URL. returns all fields..
        },
      }

Also, you could filter images and get the desired URL by using only lodash functions. By adding .then() after .fetchAll()

let entities = await strapi.query('articles').model.fetchAll({
      columns: ['id', 'title', 'body'],
      withRelated: ['images'],
    }).then(data => {
      let output = data.toJSON();
      output = _.map(output, (item) => {
        item.imageUrl = _.get(item, ['images', 'formats', 'thumbnail', 'url']);
        delete item.images;
        return item;
      });
      return output;
    });

Result:

[
    {
        "id": 1,
        "title": "fweq",
        "body": "fwqef"
    },
    {
        "id": 2,
        "title": "fewqf",
        "body": "fqwf",
        "imageUrl": "/uploads/thumbnail_photo_2020_03_29_16_28_23_3_bcf552acd3.jpg"
    },
    {
        "id": 3,
        "title": "fwqefqwe",
        "body": "fw"
    }
]
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