DynamoDB PartiQL: query on map key

Question

Hello,

Could you please correct the following query so that to work in DynamoDB PartiQL ?

For the table "PicturesTagging" with item structure:

```
{
  "PictureS3BucketKeyPK": {
    "S": "pics-repository#pics#samsung_M#2021#2021.01.06_jumbo_craciun#20210102_120050.jpg"
  },
  "TagsTool": {
    "S": "aws_rekognition_worker_labels_no_params"
  },
  "Tags": {
    "M": {
      "personal:data:content:labels:dominant_category": {
        "S": "Buildings and Architecture"
      },
      "personal:data:content:labels:dominant_label": {
        "S": "Building"
      }
    }
  }
}
```
I need to get those items that contains a certain key fragment:

```
SELECT PictureS3BucketKeyPK, Tags
FROM PicturesTagging 
where begins_with("Tags", 'personal:data:content:labels:')
```
The query runs succesfully, but it returns no items, while the table has a lot like those.

Thank you,  
Mihai ADAM

Answer

Hi

In your Table the Tags attribute is a Map with two attributes `personal:data:content:labels:dominant_category` and `personal:data:content:labels:dominant_label`, in your query it looks like you are trying to query on the attribute name, that is not possible you need to query on the values.

A query to fetch all items that has the `personal:data:content:labels:dominant_label` attribute with a value that starts with `Building` would look like this:

```
SELECT PictureS3BucketKeyPK, Tags
FROM PicturesTagging 
where begins_with("Tags"."personal:data:content:labels:dominant_label", 'Building')
```

Hope it helps.

DynamoDB PartiQL: query on map key

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