num_changes.md

api_name	excerpt	topics	api	hyperfunction	api_details
num_changes()	Get the number of times a counter changed from a counter aggregate	hyperfunctions	license type toolkit experimental version community function true false experimental stable 0.2.0 1.3.0	family type aggregates counters and gauges accessor counter_agg()	summary signatures parameters examples Get the number of times the counter changed during the period summarized by the counter aggregate. Any change is counted, including resets to zero. language code sql num_changes( summary CounterSummary ) RETURNS BIGINT required returns name type description summary CounterSummary A counter summary created using [`counter_agg`](#counter_agg) column type description num_changes BIGINT The number of times the counter changed description command Get the number of times the counter changed over each 15-minute interval. code SELECT id, bucket, num_changes(summary) FROM ( SELECT id, time_bucket('15 min'::interval, ts) AS bucket, counter_agg(ts, val) AS summary FROM foo GROUP BY id, time_bucket('15 min'::interval, ts) ) t