In some situations, MySQL will just use an index to fulfill the requirement of an ORDER BY or GROUP BY statement without extra sorting.Although ORDER BY will not have the exact match with index, index can still be used as long as the portion that is not included in the index is included in the where clause.The following queries will all use index to process the ORDER BY or GROUP BY part:SELECT * FROM t1 ORDER BY key_part1,key_part2,... ;SELECT * FROM t1 WHERE key_part1=constant ORDER BY key_part2;SELECT * FROM t1 WHERE key_part1=constant GROUP BY key_part2;SELECT * FROM t1 ORDER BY key_part1 D...

TIOBE released the programming index for September 2012. There is no big change for this month compared to last month, the top 3 are still C, Java and Objective-C. In top 20, only Transact-SQL exchanged the position with VB.NET. Java shows trend of drop, will it be worse because of the ignorance of Java's vulnerabilities by Oracle.This index shows that the programing lnaguage market is quite normal, no big events. Except Objective-C, in recent years there are no other new languages which have big rank leap. If we expect that Scala, Dart or Clojure have big breakthrough, then how long should we...