… dynamic is this information If information rarely changes or is static it may be …analyzed by the query. For example SELECT COUNT(*) FROM links WHERE domain = ‘mysql.com’; will …IN(5,7,4,56) instead. Do not however be obsessed with this. I’ve seen people trying to join all queries in single UNION…
Post: Multi Column indexes vs Index Merge
September 19, 2009 By 31 Comments
…union(i1,i2); Using where | +—-+————-+———+————-+—————-+——-+———+——+——–+———————————+ 1 row in set (0.00 sec) This query takes 660ms to execute. now if we change… can’t be used for such queries. P.S The tests were done in MySQL 5…
