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See a very comprehensive SQL optimization article, in the development of the work often do not consider the performance of the lack of (at the beginning of the data volume is not seen the difference in speed). But the more you write, the more you

optimization Problems of databasefirst, the question of the proposedIn the early stage of application system development, due to less development database data, the query SQL statement, complex view of the writing of the performance of the SQL

1. To optimize the query, to avoid full table scanning, first consider the where and order by the columns involved in the index.2. Avoid null-valued fields in the WHERE clause, which will cause the engine to discard full-table scans using the index,

See a very comprehensive SQL optimization article, in the development of the work often do not consider the performance of the lack of (at the beginning of the data volume is not seen the difference in speed). But the more you write, the more you

1. Efficient SQL statement design:Typically, you can use the following methods to optimize the performance of SQL for data operations:(1) Reduce the number of queries to the database, that is, reduce requests for system resources, using distributed

============ Recommended ============csdn:http://blog.csdn.net/e3002/article/details/1817941= = = How to optimize SQL statements = =(1) Select the most efficient table name order (valid only in the rule-based optimizer):    Oracle's parser processes

1.ORACLE Optimizer total 3 kinds A, rule (rule-based) B, cost (based on costs) C, CHOOSE (optional) Set the default optimizer to pass various declarations of optimizer_mode parameters in the Init.ora file, such as

[Optimization] 34 SQL Optimizations We must not only write SQL statements, but also write SQL statements with excellent performance. The following section describes how to learn, extract, and summarizeShare the information with you!(1) select the

(1) Select the most efficient table name order (valid only in the rule-based optimizer):The Oracle parser processes the table names in the FROM clause in a right-to-left order, and the FROM clause is written in the final table (the underlying table,

In the early stage of application system development, due to less development database data, the query SQL statement, complex view of the writing of the performance of the SQL statement is not good or bad, but if the application system submitted to