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stats: Mathematical statistics in SQLite

The sqlean-stats extension provides common statistical functions.

Reference • Acknowledgements • Installation and usage

Reference

There are aggregate functions such as median and percentile, and a table-valued sequence function for generating sequences.

Aggregate functions

  • stats_median(x) — median (50th percentile),
  • stats_p25(x) — 25th percentile,
  • stats_p75(x) — 75th percentile,
  • stats_p90(x) — 90th percentile,
  • stats_p95(x) — 95th percentile,
  • stats_p99(x) — 99th percentile,
  • stats_perc(x, p) — custom percentile (p between 0 and 100),
  • stats_stddev(x) or stats_stddev_samp(x) — sample standard deviation,
  • stats_stddev_pop(x) — population standard deviation,
  • stats_var(x) or stats_var_samp(x) — sample variance,
  • stats_var_pop(x) — population variance.

stats_seq

stats_seq(start[, stop[, step]])
generate_series(start[, stop[, step]])

This table-valued function generates a sequence of integer values starting with start, ending with stop (inclusive) with an optional step.

Generate all integers from 1 to 99:

select * from stats_seq(1, 99);

Generate all multiples of 5 less than or equal to 100:

select * from stats_seq(5, 100, 5);

Generate 20 random integer values:

select random() from stats_seq(1, 20);

The stats_seq() table has a single result column named value holding integer values, and a number of rows determined by the parameters start, stop, and step. The first row of the table has a value of start. Subsequent rows increase by step up to stop.

stop defaults to 9223372036854775807. step defaults to 1.

Acknowledgements

Adapted from extension-functions.c by Liam Healy, percentile.c and series.c by D. Richard Hipp.

Installation and usage

SQLite command-line interface:

sqlite> .load ./stats
sqlite> select stats_median(value) from stats_seq(1, 99);

See How to install an extension for usage with IDE, Python, etc.

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