… | +———————————-+ 2 rows in set (0.00 sec) mysql> explain SELECT sql_no_cache name FROM people WHERE age in(18,19… age=18 order by last_online desc limit 10) UNION ALL (select * from people where age=19 order by last_online desc limit 10) UNION ALL (select * from people where age=20 order by last_online desc limit 10) ORDER BY last…
Post: MySQL: Followup on UNION for query optimization, Query profiling
August 14, 2006 By 12 Comments
Post: Shard-Query turbo charges Infobright community edition (ICE)
May 6, 2011 By 22 Comments
…test. This VM was rebooted between tests. A SQL script was fed to the run_query…. IN clauses, subqueries in the FROM clause, UNION or UNION ALL clauses. If none of those features are …) WHERE Year BETWEEN 1980 and 2011 GROUP BY dest.CityName ORDER BY 2 DESC; Finally, Shard-Query performance continues…
Post: Distributed Set Processing with Shard-Query
May 14, 2011 By 27 Comments
…. This allows BETWEEN, IN, subqueries in the FROM clause, and UNION operations to operate fully in parallel. Distributed set processing is…_date.date_id) WHERE dim_date.Year IN (2008) GROUP BY 1 ORDER BY NULL [1] => SELECT origin_airport_id AS `origin_airport….date_id) WHERE dim_date.Year IN (2009) GROUP BY 1 ORDER BY NULL ) — AGGREGATION SQL: SELECT `origin_airport_id`, SUM(`count(*)`) AS `count…
Comment: Duplicate indexes and redundant indexes
January 19, 2012 By 38 Comments
…sql …BY a.table_schema, a.table_name, a.constraint_name, a.constraint_type, b.referenced_table_name, b.referenced_column_name UNION…BY table_schema, table_name, constraint_name, constraint_type, referenced_table_name, referenced_column_name ORDER BY…
