order by index

MySQL index details, MySQL index detailsI. Introduction to index basics 1.1 In MySQL, indexes are also called keys. They are a data structure that the storage engine uses to quickly find records. Indexes are critical to good performance. Especially

In the database, the index is a special object, it is a database structure that can speed up the data retrieval, it can quickly find the necessary content from the large amount of data, make the data query without retrieving the whole database. An

ReprintedBytes IndexYou can use indexes to quickly access specific information in database tables. An index is a structure that sorts the values of one or more columns in a database table (for example, the last name (lname) column of the employee

    I. Index Introduction 1.1 index creation Syntax: Create uniuqe | bitmap index . ON . (| ASC | DESC, | ASC | DESC ,...) TABLESPACE STORAGE LOGGING | NOLOGGING COMPUTE STATISTICS NOCOMPRESS | COMPRESS NOSORT | REVERSE PARTITION | global

SYS. dm_exec_requests is a powerful tool to check the performance bottleneck of SQL Server. Update statistics t_goods with fullscan --- Update table statisticsThe index leaves of clustered indexes are the data itself.The leaf node of the

The MySQL order BY keyword is used to classify the data in the record. MySQL ORDER BY keyword classified by keyword The ORDER BY keyword is used to classify the data in a record. MySQL ORDER BY syntax The code is as follows Copy

A Index Introduction1.1 Creation syntax of the index:CREATE UNIUQE | BITMAP INDEX .On .( | ASC | DESC, | ASC | DESC,...)Tablespace STORAGE LOGGING | NologgingCOMPUTE STATISTICSnocompress | CompressNosort | REVERSEPARTITION | GLOBAL

This article is transferred from: Http://www.cnblogs.com/abcdwxc/archive/2007/12/11/990274.html ----------------------- Creates an index for a given table or view.Only the owner of a table or view can create an index for the table. The owner of a

MySQL InnoDB b-tree index using TipsHere is the main discussion about the use of InnoDB B-tree index, do not mention the design, just use. The B-tree index primarily acts on the Where and order by clauses. It's all discussed here in the mysql-server-

Transferred from: http://blog.csdn.net/caomiao2006/article/details/52140993because group by actually sorts, and the group by is mostly just a sort of grouping operation, compared to order by. of course, if you use some other aggregate functions when