Unable to filter Azure resource using tags through cli

I have multiple namespace resources with tag site:prod

az tag list --resource-id "subscriptions/[subsc_id]/resourceGroups/[rg_id]/providers/Microsoft.ServiceBus/namespaces/[ns_name]"         
{
  "id": "/subscriptions/[subsc_id]/resourceGroups/[rg_id]/providers/Microsoft.ServiceBus/namespaces/[ns_name]/providers/Microsoft.Resources/tags/default",
  "name": "default",
  "properties": {
    "tags": {
      "module": "payment",
      "site": "prod"
    }
  },
  "resourceGroup": "[rg_id]",
  "type": "Microsoft.Resources/tags"
}

I want retrieve all resource such as above which have site:prod tag using cli command, by running following:

az servicebus namespace list --subscription "[subsc_id]" --query '[?tags.site=="prod"]'

However, running above command produces completely opposite output such that none of the returned namespace objects have tag site:prod on them.

What am I doing wrong here?

I found the problem in your code: you are using " (quotation) incorrectly:

az servicebus namespace list --subscription "Subscription name" --query "[?tags.site=='prod']"

You should keep " at the starting of query and ' in middle of query

Alternatively,

>Unable to filter Azure resource using tags through cli

You can simply use below command to get all the resources names which have tags site=prod:

$s= az resource list --tag site=prod 
$res=$s | ConvertFrom-json          
$res.name