Then you would have to write an xtypes extension
<https://github.com/weewx/weewx/wiki/WeeWX-V4-user-defined-types>.
It would look something like this (NOT TESTED):
import weedb
import weewx.xtypes
class LastNonZero(weewx.xtypes.XType):
def get_aggregate(self, obs_type, timespan, aggregate_type, db_manager,
**option_dict):
if aggregate_type != 'lastnonzero':
raise weewx.UnknownAggregation(aggregate_type)
interpolate_dict = {
'aggregate_type': aggregate_type,
'obs_type': obs_type,
'table_name': db_manager.table_name,
'start': timespan.start,
'stop': timespan.stop
}
select_stmt = "SELECT %(obs_type)s FROM %(table_name)s " \
"WHERE dateTime > %(start)s AND dateTime <= %(stop)s
" \
"AND %(obs_type)s IS NOT NULL " \
"AND %(obs_type)s != 0 " \
"ORDER BY dateTime DESC LIMIT 1" % interpolate_dict
try:
row = db_manager.getSql(select_stmt)
except weedb.NoColumnError:
raise weewx.UnknownType(obs_type)
value = row[0] if row else None
u, g = weewx.units.getStandardUnitType(db_manager.std_unit_system,
obs_type,
aggregate_type)
return weewx.units.ValueTuple(value, u, g)
Then you could use it:
<p>This month's last non-null and non-zero temperature is
$month.outTemp.lastnonzero</p>
On Tue, Nov 17, 2020 at 6:46 AM steeple ian <[email protected]> wrote:
> Thanks Tom,
>
> It worked fine, I did actually try that and it returned a zero (not
> realising I had a zero in the database) and thought it had not worked
> correctly. So if I want to eliminate the zeros as well?
>
> On Tue, 17 Nov 2020 at 12:38, Tom Keffer <[email protected]> wrote:
>
>> The aggregation type 'last' should do what you want:
>>
>> <p>The last non-null temperature this month is: $month.outTemp.last</p>
>>
>>
>> On Tue, Nov 17, 2020 at 4:25 AM [email protected] <[email protected]>
>> wrote:
>>
>>> Hi,
>>>
>>> Trying to find a 'WeeWX way' to find the last non-NULL record from the
>>> database using a .tmpl file.
>>>
>>> Nothing obvious jumps out for me from the documentation. Does anybody
>>> have any ideas?
>>>
>>> Thanks,
>>> Ian
>>>
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