How to query nested document and return String result?

Did a query Product.findOne({'variation.sku': req.params.productVariationSKU },{'_id': 0, 'variation.price' :1}) to find the price of a product variation.

But result returned price of all product variations. Need help to find where went wrong!

Below is product schema:

var ProductSchema = new Schema({      productId: {          type: Number,          required: [true, 'Product ID is required'],          unique: true      },      sku: String,      category: [String],      language: {          type: String,          lowercase: true,          maxlength: 2,          required: [true, 'Language code required'],          index: true,          unique: true      },      name: {          type: String,          required: [true, 'Product name is required']      },      descLong: String,      descShort: String,      mainImageURL: String,      galleryImageURL: [String],      variation: [{          sku: String,          option: [{              label: String,              value: String,          }],          inventory: [{              name: String,              quantity: Number,              country: String          }],          inStock: Boolean,          price: mongoose.Types.Decimal128      }],      attribute: [{          label: String,          value: [String]      }],      inStock: Boolean,      currencySymbol: String,      slug: String,      metaTitle: String,      metaDescription: String,      relatedAccessory: [Number],      htmlContentBefore: String,      htmlContentAfter: String  });  

Below is product object from Postman:

{      "category": [],      "galleryImageURL": [          "TEST.png"      ],      "relatedAccessory": [],      "_id": "5feae4418d686300176dfbbd",      "productId": 1,      "language": "en",      "name": "TEST PRODUCT",      "descLong": "<p><strong>This is a long description</strong></p>",      "descShort": "Short Description",      "mainImageURL": "TEST.png",      "variation": [          {              "option": [                  {                      "_id": "5feae4418d686300176dfbbf",                      "label": "Color",                      "value": "Black"                  }              ],              "inventory": [],              "_id": "5feae4418d686300176dfbbe",              "sku": "P-1",              "inStock": true,              "price": "45"          },          {              "option": [                  {                      "_id": "5feae4418d686300176dfbc1",                      "label": "Color",                      "value": "White"                  }              ],              "inventory": [],              "_id": "5feae4418d686300176dfbc0",              "sku": "P-2",              "inStock": true,              "price": "45"          }      ],      "attribute": [          {              "value": [                  "Black",                  "White"              ],              "_id": "5feae4418d686300176dfbc2",              "label": "Color"          }      ],      "currencySymbol": "£",      "slug": "test",      "metaTitle": "testmeta",      "metaDescription": "This is meta description",      "__v": 0  }  

Below is API function:

app.get('/API/Product/GetProductVariationPrice/:productVariationSKU', async(req, res) => {    try{      res.send(await Product.findOne({'variation.sku': req.params.productVariationSKU },{'_id': 0, variation :1}));    } catch (err) {      res.status(500).send(err);    }  });  

Returned result from Postman:

{      "variation": [          {              "price": "45"          },          {              "price": "45"          }      ]  }  

Question: How can I get just "45" of variation SKU "P-1"? As the result currently returns the price of variation 'P-2' as well which is not wanted. SKU should be based on the param passed to the API.

https://stackoverflow.com/questions/65802316/how-to-query-nested-document-and-return-string-result January 20, 2021 at 10:34AM