Database

[{"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}]

Query

db.collection.find({"variation.sku":"P-1"},{"_id":0,variation:{$reduce:{input:"$variation",initialValue:0,in:{$cond:[{$eq:["$$this.sku","P-1"]},"$$this.price","$$value"]}}}})

Result