So, I have my mappings as this
and my query request object as referred to [this link](https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-bucket-nested-aggregation.html)
Query JSON
{
"size": 0,
"query": {
"nested": {
"path": "custom_fields",
"query": {
"bool": {
"must": [
{
"match": {
"custom_fields.label": "Application Module"
}
}
]
}
}
}
},
"aggs": {
"agg_custom_field": {
"nested": {
"path": "custom_fields"
}
},
"aggs": {
"agg_value": {
"cardinality": {
"field": "custom_fields.value"
}
}
}
}
}
Error Response
{
"error": {
"root_cause": [
{
"type": "parsing_exception",
"reason": "Unknown aggregation type [agg_value]",
"line": 26,
"col": 24
}
],
"type": "parsing_exception",
"reason": "Unknown aggregation type [agg_value]",
"line": 26,
"col": 24,
"caused_by": {
"type": "named_object_not_found_exception",
"reason": "[26:24] unknown field [agg_value]"
}
},
"status": 400
}