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最新文章列表
《Pro Oracle SQL》Chapter 8 -- 8.5 Lead and Lag
Lead and Lag
(page 249)
Lag and lead functions provide inter-row referencing ability. Lag provides the ability to access prior row in the result set. The lead function allows acces ...
《Pro Oracle SQL》Chapter 8 -- 8.4Aggregation Functions
Aggregation Functions 聚合函数 (page 246)
Aggregation functions can operate in analytic mode or conventional non-analytic mode. Aggregation
functions in non-analytic mo ...
《Pro Oracle SQL》Chapter 8 -- 8.1-8.2 Anatomy of Analytic Functions -8.3
Riyaj Shamsudeen (page 243)
Online Analytic Processing (OLAP)
queries perform multi-dimensional aggregation and are useful in
business decision-making processes in areas such as sales, market ...
《Pro Oracle SQL》Chapter2--2.13 SQL Execution – Putting It All Together
SQL Execution – Putting It All Together SQL执行--把所有放在一起
(page 81)
Now that I’ve covered the details, I’m ready to put the whole picture
of how a SQL statement executes together. Fi ...
《Pro Oracle SQL》CHAPTER2--2.12Executing the Plan and Fetching Rows
Executing the Plan and Fetching Rows 执行计划和取出行
(page 78)
After the optimizer determines the plan and stores it in the library cache for later reuse, the next step i ...
《Pro Oracle SQL》CHAPTER2--2.11 Determining the Execution Plan
Determining the Execution Plan 确定执行计划 (page 74)
When a hard parse occurs, Oracle will determine which execution plan is best for the query. An
execution plan is simply the set of steps ...
《Pro Oracle SQL》CHAPTER2--2.10 Query Rewrite with Materialized Views
Query Rewrite with Materialized Views 用物化视图重写查询
(page 72)
Query rewrite is a transformation that occurs when a query, or a portion
of a query , has been saved as a materialized vi ...
《Pro Oracle SQL》CHAPTER2--2.9 Predicate Pushing
Predicate Pushing 谓词推进
(page 69)
Predicate pushing is used to apply the predicates from a containing query block into a non-mergeable
query block.
The goal is to allow an ...
《Pro Oracle SQL》CHAPTER2--2.8 Subquery Unnesting
Subquery Unnesting 子查询反嵌套
(page 66)
Subquery unnesting is similar to view merging in that just like a view a subquery is represented by a
separate que ...
《Pro Oracle SQL》CHAPTER2--2.7 View Merging
View Merging 视图合并
(Page 62)
As the name implies, view merging is a transformation that expands views, either in-line views or stored views, into separate query blocks that can either ...
《Pro Oracle SQL》CHAPTER2--2.6Query Transformation
Query Transformation 查询变换 (Page 61)
Prior to the development of the execution plan, a step called query transformation occurs.
This step
happens just after a query is checked for synt ...
《Pro Oracle SQL》Charpter2 --2.5 SGA – The Buffer Cache
SGA – The Buffer Cache SGA-缓冲区缓存
(page59)
The buffer cache is one of the largest components of the SGA.
It stores database blocks after they have been read from disk or before t ...
《Pro Oracle SQL》Chapter 2--2.4 Identical Statements
2.4 Identical Statements 同样的语句
(page56)
In order for Oracle to determine if a statement has been previously executed, it will check the library
cache for the ident ...
《Pro Oracle SQL》CHAPTER2--2.3 The Library Cache
The Library Cache 库缓存
(page 54)
The first thing that must happen to every SQL statement you execute is that it must be parsed and
loaded into the library cache.
T ...
《Pro Oracle SQL》Chapter2-2.2 SGA – The Shared Pool
2.2 SGA – The Shared Pool 共享池 (page 53)
The shared pool is one of the most critical memory components particularly when it comes to how SQL executes. The way you write SQL doesn’t ...
《Pro Oracle SQL》 Chapter2--2.1 Oracle Architecture Basics
Chapter 2 SQL Execution SQL的执行
Karen Morton (page51)
You likely learned the mechanics of writing basic SQL in a relatively short period of time. Over the course of a fe ...
《Pro Oracle SQL》Chapter7--7.10GROUP BY Restrictions
7.10 GROUP BY的限制 (page 217)
Your study of GROUP BY would be incomplete without considering what it cannot do. The list of restrictions placed on GROUP BY is not very long. The restri ...
《Pro Oracle SQL》Chapter7--7.9GROUPING SETS and ROLLUP()
7.9 GROUPING SETS and ROLLUP()
(page 214)
There is yet another method that may be used to obtain the results seen in the previous two examples. The GROUPING SETS() extension to GROUP BY ...
《Pro Oracle SQL》Chapter7 -- 7.8Extending Reports With GROUPING_ID()
7.8 Extending Reports With GROUPING_ID() 使用GROUPING_ID()扩展报告
(page210)
The GROUPING_ID()function is relatively new compared to the GROUPING() function, having been
introduced in Oracle 9 ...
《Pro Oracle SQL》Chapter7 -- 7.7Extending Reports with GROUPING()
7.7Extending Reports with GROUPING() 用GROUPING()函数扩展报告 (page209)
Another use of GROUPING() is in the HAVING clause, where it can be used to control which aggregation levels appear in the out ...