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mojunbin：
这个不能不顶。
《Pro Oracle SQL》 Chapter2--2.1 Oracle Architecture Basics -
Branding：
谢谢，获益匪浅
《Pro Oracle SQL》--chapter 5--5.6 Building Logical Expressions -
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《Pro Oracle SQL》--Chapter 5--5.4 Questions about the Question -
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谢谢
《Pro Oracle SQL》 翻译序 -- 读书心得 -
jiaoshiguoke：
继续 加油
《Pro Oracle SQL》--Chapter 6--6.1 Explain Plans--之三
文章列表
Index Skip Scan 索引跳跃扫描
(page 107)
An index skip scan is chosen when the predicate contains a condition on a non-leading column in an
index and the leading columns are fairly distinct
.
In earlier releases of Oracle, if a predicate used a
column that wasn’t the leading ...
Index Full Scan 索引全扫描
(page 103)
An index full scan is chosen under several conditions including: when there is no predicate but the
column list can be satisfied through an index on a column, the predicate contains a condition on a
non-leading column in an index, or the data can be ret ...
Index range scan 索引范围扫描
(page 101)
An index range scan is chosen when a predicate contains a condition that will return a range of data.
The index can be unique or non-unique as it is the condition that determines whether or not multiple
rows will be returned or not. The conditi ...
Index Unique Scan 索引唯一扫描
(page 78)
An index unique scan is chosen when a predicate contains a condition using a column defined with a
UNIQUE or PRIMARY KEY index. These types of indexes guarantee that only one row will ever be returned for a specified value ...
Index Scan Types 索引扫描类型
(page 97)
There are several different types of index scans but each share some common ground in how they must traverse the index structure to access the leaf block entries that match the values being searched.
First, the root block of the ...
Index Scan Access Methods 索引扫描访问方法
(page 95)
If you have a book about U.S. Presidents and want to find information on Jimmy Carter, you could start
on the first page and visually scan each page until you came to the section of the book about Carter.
However, it would take a lo ...
Full Scans and the Highwater Mark 全扫描和高水标识
A final point of note regarding full table scans is that as the multiblock read calls for the scan are
made, Oracle will read blocks up to the highwater mark in the table. The highwater mark marks the
last block in the ...
Full Scans and Throwaway 全扫描和“抛弃”
Always remember that whether or not a full scan will be an effective choice depends on the number of
blocks that will need to be read as much as on how many rows will end up in the final result set. How
the data is stored plays an important role in the ...
Chapter3 Access and Join Methods 访问和连接方法
Karen Morton (page 83)
The optimizer must determine how to access the data your SQL statements require. You formulate your statement and the optimizer, during a hard parse, will figure out which operations should provide the data in the most eff ...
Advanced topics 高级主题
(page 268)
A few advanced topics about the analytic functions are worthy of discussion. I will discuss topics such as dynamic analytic statements, nesting of analytic functions, parallelism, and PGA size.
关于分析函数的一些高 ...
Performance Tuning 性能调优
(page 266)
Analytic functions are very useful in tuning complex SQL statements. Inter-row referencing, aggregation at multiple levels, and nth-row access are a few of the important features analytic functions provide. For example, a typical query fetching both ...
NTILE
（page 263）
The NTILE function divides an ordered set of rows in a data partition, groups them in to
buckets
, and
assigns a unique group number to each group.
This function is useful in statistical analysis. For example,
if you want to remove the outliers (values that ...
Ratio_to_report
(page 259)
The analytic function ratio_to_report calculates the ratio of a value to the sum of values in the data
partition. If the partitioning clause is not specified, this function calculates the ratio of a value to the sum
values in the whole res ...
Other Analytic Functions (page254)
Oracle Database implements a great many other analytic functions. Some of those more commonly used are described in the following subsections. The functions that follow are the ones that should be on your short list
of good functions to know about. ...
First_value & Last_value
(page 252)
First_value and
last_value functions are useful in calculating the maximum and minimum
values in an orered result set. The first_value function retrieves the
column value from the first row in window of rows, and the last_value ...