extended_statistics_multicolumn_selectivity

📊 Create Extended Statistics for Better Multi-Column Plans

Standard single-column histograms can misestimate row counts for combined filters. MySQL’s extended statistics let you track correlation and distinct counts across multiple columns, improving join and range query selectivity.

CREATE STATISTICS stat_user_region_age
  ON users (region_id, age)
  COMMENT 'Track correlation for region and age';
ANALYZE TABLE users;

EXPLAIN SELECT *
FROM users
WHERE region_id = 5 AND age BETWEEN 30 AND 40;