SQL: HAVING without GROUP BY

[astefan]

sql> select 1 having count(*) > 0;
Bad request [Found 1 problem(s)
line 1:17: Cannot use WHERE filtering on aggregate function [COUNT(1)], use HAVING instead]

The error message is confusing.

[elasticmachine]

Pinging @elastic/es-search

[astefan]

For a query like select count(1) from calcs group by str0 having count(1) > 0 we do generate an ES query, which seems valid and does work:

{
    "size": 0,
    "_source": false,
    "stored_fields": "_none_",
    "aggregations": {
        "groupby": {
            "composite": {
                "size": 1000,
                "sources": [
                    {
                        "53415": {
                            "terms": {
                                "field": "str0",
                                "missing_bucket": true,
                                "order": "asc"
                            }
                        }
                    }
                ]
            },
            "aggregations": {
                "having.53424": {
                    "bucket_selector": {
                        "buckets_path": {
                            "a0": "_count"
                        },
                        "script": {
                            "source": "InternalSqlScriptUtils.nullSafeFilter(InternalSqlScriptUtils.gt(params.a0,params.v0))",
                            "lang": "painless",
                            "params": {
                                "v0": 0
                            }
                        },
                        "gap_policy": "skip"
                    }
                }
            }
        }
    }
}