DECODE_HISTOGRAM()

Overview

Returns a string of comma-separated numeric values that correspond to the probability distribution represented by a histogram of the given histogram type.

See also: Functions in 10.6 ES, in 10.5 ES, and in 10.4 ES

EXAMPLES

CREATE TABLE t (
 c1 INT,
 c2 INT
);
INSERT INTO t VALUES
  (1,1), (2,2), (3,3), (4,4), (5,5), (6,6), (7,7),
  (8,8), (9,9), (10,10), (11,20), (12,30), (13,40),
  (14,50), (15,60), (16,70), (17,80), (18,90), (20,100);
SET histogram_size=10, histogram_type=SINGLE_PREC_HB;
ANALYZE TABLE t PERSISTENT FOR ALL;
+--------+---------+----------+-----------------------------------------+
| Table  | Op      | Msg_type | Msg_text                                |
+--------+---------+----------+-----------------------------------------+
| test.t | analyze | status   | Engine-independent statistics collected |
| test.t | analyze | status   | OK                                      |
+--------+---------+----------+-----------------------------------------+
SELECT hist_type, HEX(histogram), DECODE_HISTOGRAM(hist_type,histogram)
 FROM mysql.column_stats
 WHERE db_name='test' and table_name='t';
+----------------+-----------------+---------------------------------------+
| hist_type      | HEX(histogram)  | DECODE_HISTOGRAM(hist_type,histogram) |
+----------------+-----------------+---------------------------------------+
| SINGLE_PREC_HB | [HEX_DIGITS...] | 0.00000,[...]                         |
| SINGLE_PREC_HB | [HEX_DIGITS...] | 0.00000,[...]                         |
+----------------+-----------------+---------------------------------------+

CHANGE HISTORY

Release Series

History

10.6 Enterprise

  • Present starting in MariaDB Enterprise Server 10.6.4-1.

10.5 Enterprise

  • Present starting in MariaDB Enterprise Server 10.5.3-1.

10.4 Enterprise

  • Present starting in MariaDB Enterprise Server 10.4.6-1.

EXTERNAL REFERENCES