原创 分析函數詳解
Introduction Probably the easiest way to understand analytic functions is to start by looking at aggregate functions.
2019-02-22 22:50:40
原创 DBMS_XPLAN : Display Oracle Execution Plans
The DBMS_XPLAN package is used to format the output of an explain plan. It was introduced in Oracle 9i as a replacem
2018-09-11 02:36:37
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原创 EXPLAIN PLAN Usage
EXPLAIN PLAN UsageWhen a SQL statement is passed to the server the Cost Based Optimizer (CBO) uses database statistics t
2018-09-11 02:36:28
原创 Hierarchical queries 分層查詢
A relational database does not store data in a hierarchical way. Then how do I get the data in a hierarchical manner? He
2018-09-11 02:36:25