DECODE_HISTOGRAM()
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The parent of this page is: Functions for MariaDB Enterprise Server
Topics on this page:
Overview
Returns a string of comma-separated numeric values that correspond to the probability distribution represented by a histogram of the given histogram type.
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
EXTERNAL REFERENCES
Additional information on this topic may be found in the MariaDB Public Knowledge Base.