Support for semantic date queries

The idea is that we add support for queries that look like this:

where: {
  myDateTime: {
    _semantic: {
      value: "TODAY",
      timezone: "+6:00"
    }
  }
}

Timezone could default to server time.

{
  myDateTime: {
    _semantic: {
      value: "NEXT_N_DAYS",
      n: 22
    }
  }
}

{
  myDateTime: {
    _semantic: {
      value: "PAST_N_WEEKS",
      timezone: "+6:00",
      n: 3
    }
  }
}

{
  myDateTime: {
    _semantic: {
      value: "LAST_MONTH",
      timezone: "+6:00"
    }
  }
}

{
  myDateTime: {
    _semantic: {
      value: "NEXT_N_HOURS",
      timezone: "+6:00",
      n: 3
    }
  }
}

These are inspired by the Salesforce API which calls them literals. See: https://developer.salesforce.com/docs/atlas.en-us.soql_sosl.meta/soql_sosl/sforce_api_calls_soql_select_dateformats.htm

The SQL can be implemented something like this:

Yesterday for example:

(
    "myDateTimeField" >= (date_trunc('DAY', now() AT TIME ZONE '+6:00') - '1 DAY'::INTERVAL) AT TIME ZONE '+6:00' AND "myDateTimeField" < (date_trunc('DAY', now() AT TIME ZONE '+6:00')) AT TIME ZONE '+6:00'
    )

Or parameterized:

pg.query(
  "?? >= (date_trunc('DAY', now() AT TIME ZONE ?) - '1 DAY'::INTERVAL) AT TIME ZONE ? AND ?? < (date_trunc('DAY', now() AT TIME ZONE ?)) AT TIME ZONE ?", 
 [field, zone, zone, field, zone, zone]
)

I can collaborate to produce the SQL required for the other semantic dates that we want to support if this feature request has merit.

[treyhuffine]

Is there any movement on this? This would be an awesome addition!

[cthurston]

Salesforce does it this way: “PAST_N_WEEKS:3” Which I didn’t like as much as having n outside the string because the client would have to build the string rather than just pass n as a variable.

I suppose you could put the timezone in as well: “PAST_N_WEEKS:3:+6:00” But now the timezone has a colon so you may want a different delimiter. “PAST_N_WEEKS,3,+6:00”

Looks impossible to validate.

_semantic: "PAST_N_WEEKS,3,+6:00"

OR

We could make them all keys:

_semantic: {
   _yesterday: true
}
_semantic: {
   _yesterday: 1
}

_semantic: {
   _past_n_weeks: 3
   _timezone: "+6:00"
}

or some combination with some string parsing

_semantic: {
   _yesterday: "+6:00"
}

_semantic: {
   _past_n_weeks: "3,+6:00"
}

OR

Nesting with a required interval-type object

_semantic: {
   _yesterday: {
    _timezone: "+6:00"
    _value: 1
  }
}

defaults to server timezone and _value of 1 maybe

_semantic: {
   _yesterday: {}
}

_semantic: {
   _past_n_weeks: {
     _timezone: "+6:00"
     _value: 3
  }
}

The nested syntax would look great in graphiQL.

With the keys they could even be taken out of the _semantic namespace and be top level, but maybe too messy to have _gte and _yesterday on the same tier.