June 19, 2013

Post: EXPLAIN EXTENDED can tell you all kinds of interesting things

…in set, 1 warning (0.00 sec) mysql> show warnings; +——-+——+——————————————————————————-+ | Level | Code | Message | +——-+——+——————————————————————————-+ | Note | 1003 | select `test…

Post: Extended EXPLAIN

… where | +—-+————-+——–+——-+—————+———+———+——+——–+————-+ 1 row in set, 1 warning (0.02 sec) mysql> show warnings \G *************************** 1. row *************************** Level: Note Code: 1003 Message: select `test`.`sbtest`.`id` AS…

Post: JOIN Performance & Charsets

… index 2 rows in set, 1 warning (0.00 sec) mysql> SHOW WARNINGS\G *************************** 1. row *************************** Level: Note Code: 1003 Message: select sql_no_cache count… index 2 rows in set, 1 warning (0.00 sec) mysql> SHOW WARNINGS\G *************************** 1. row *************************** Level: Note Code: 1003 Message: select sql_no_cache count…

Comment: COUNT(*) vs COUNT(col)

… 1 row in set, 1 warning (0.00 sec) mysql> show warnings; +——-+——+———————————————————+ | Level | Code | Message | +——-+——+———————————————————+ | Note | 1003 | select count(0) AS `count… 1 row in set, 1 warning (0.00 sec) mysql> show warnings; +——-+——+———————————————————+ | Level | Code | Message | +——-+——+———————————————————+ | Note | 1003 | select count(1) AS `count…

Post: A workaround for the performance problems of TEMPTABLE views

… | Note | 1003 | select…mysql> show warnings; +———+——+——————————————————————————-+ | Level | Code | Message | +———+——+——————————————————————————-+ | Warning

Comment: EXPLAIN EXTENDED can tell you all kinds of interesting things

warning (0.01 sec) mysql> show warnings; …| +——-+——+—————————————————————————————————————————————————————————-+ | Note | 1003 | select …