Hi so I have a simple table as \d sensor_values_days; Table "public.sensor_values_days" Column | Type | Modifiers -----------+--------------------------+------------------------------ ts | timestamp with time zone | not null value | double precision | not null default 'NaN'::real sensor_id | integer | not null Indexes: "timestamp_id_index" UNIQUE CONSTRAINT, btree (ts, sensor_id) Foreign-key constraints: "sensor_values_days_sensor_id_fkey" FOREIGN KEY (sensor_id) REFERENCES sensors(id) and I have a simple query that fails Ie SELECT sensor_id, MAX(ts), date_trunc('day', ts), COALESCE(MAX(value), 'NaN')::float FROM sensor_values_days WHERE ts > '2017-10-06 00:01:01+00' AND ts < '2017-10-06 23:59:59+00' GROUP BY 1, 3 ORDER BY 1, 2; sensor_id | max | date_trunc | coalesce -----------+-----+------------+---------- (0 rows) If I remove the timezone part of the start date I get results. Ie SELECT sensor_id, MAX(ts), date_trunc('day', ts), COALESCE(MAX(value), 'NaN')::float FROM sensor_values_days WHERE ts > '2017-10-06 00:01:01' AND ts < '2017-10-06 23:59:59+00' GROUP BY 1, 3 ORDER BY 1, 2; sensor_id | max | date_trunc | coalesce -----------+------------------------+------------------------+---------- 597551 | 2017-10-06 01:00:00+01 | 2017-10-06 00:00:00+01 | 13763 597552 | 2017-10-06 01:00:00+01 | 2017-10-06 00:00:00+01 | 8168 597553 | 2017-10-06 01:00:00+01 | 2017-10-06 00:00:00+01 | 9441 .... ... .. I'm sure I am doing something silly but can't see what. Does anyone know what is going on here ? I am using Postgres 9.5 Thanks -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general