**Is your feature request related to a problem?** [PPL does not support](https://github.com/opensearch-project/sql/blob/main/docs/user/ppl/limitations/limitations.rst#unsupported-opensearch-field-types) [OpenSearch Constant keyword field type](https://docs.opensearch.org/docs/latest/field-types/supported-field-types/constant-keyword/) **What solution would you like?** Support [OpenSearch Constant keyword field type](https://docs.opensearch.org/docs/latest/field-types/supported-field-types/constant-keyword/) in PPL. **What alternatives have you considered?** n/a
Is your feature request related to a problem?
PPL does not support OpenSearch Constant keyword field type
What solution would you like?
Support OpenSearch Constant keyword field type in PPL.
What alternatives have you considered?
n/a