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2.3 KiB
2.3 KiB
slug | sidebar_position | sidebar_label |
---|---|---|
/en/sql-reference/aggregate-functions/reference/sparkbar | 311 | sparkbar |
sparkbar
The function plots a frequency histogram for values x
and the repetition rate y
of these values over the interval [min_x, max_x]
.
Repetitions for all x
falling into the same bucket are averaged, so data should be pre-aggregated.
Negative repetitions are ignored.
If no interval is specified, then the minimum x
is used as the interval start, and the maximum x
— as the interval end.
Otherwise, values outside the interval are ignored.
Syntax
sparkbar(buckets[, min_x, max_x])(x, y)
Parameters
buckets
— The number of segments. Type: Integer.min_x
— The interval start. Optional parameter.max_x
— The interval end. Optional parameter.
Arguments
x
— The field with values.y
— The field with the frequency of values.
Returned value
- The frequency histogram.
Example
Query:
CREATE TABLE spark_bar_data (`value` Int64, `event_date` Date) ENGINE = MergeTree ORDER BY event_date;
INSERT INTO spark_bar_data VALUES (1,'2020-01-01'), (3,'2020-01-02'), (4,'2020-01-02'), (-3,'2020-01-02'), (5,'2020-01-03'), (2,'2020-01-04'), (3,'2020-01-05'), (7,'2020-01-06'), (6,'2020-01-07'), (8,'2020-01-08'), (2,'2020-01-11');
SELECT sparkbar(9)(event_date,cnt) FROM (SELECT sum(value) as cnt, event_date FROM spark_bar_data GROUP BY event_date);
SELECT sparkbar(9, toDate('2020-01-01'), toDate('2020-01-10'))(event_date,cnt) FROM (SELECT sum(value) as cnt, event_date FROM spark_bar_data GROUP BY event_date);
Result:
┌─sparkbar(9)(event_date, cnt)─┐
│ ▂▅▂▃▆█ ▂ │
└──────────────────────────────┘
┌─sparkbar(9, toDate('2020-01-01'), toDate('2020-01-10'))(event_date, cnt)─┐
│ ▂▅▂▃▇▆█ │
└──────────────────────────────────────────────────────────────────────────┘