sql query tuning techniques in oracle

Oracle SQL query optimization for Oracle Data Scanning (2) 2. How to improve the performance of local range data scanning: 2.1 category and role of query conditions: When we initiate a SQL statement with conditions, multiple

Label:The first is the problem of fuzzy query, I started with the following conditions: SELECT * from the user where name like '% #value #% '. But how can not, as if also reported wrong. Later on the internet found a solution, is to use $ to replace the # number.1> write: Like '% $value $% ' can be,2> also found another method, but that method I tried for a long time, is not, the method is: like '% ' | | #value # | | '% ', the

, Administrativename,administrativeremark from Cet_administrativeoption (maxrecursion 0); GOOracle:1. From the root node to the child node:SELECT Administrativeid,administrativepid,administrativename,administrativeremark from Tadministrative START with Administrativepid is a NULL CONNECT by PRIOR Administrativeid=administrativepid;2. Query from child nodes to the root node:SELECT Administrativeid,administrativepid,administrativename,administrativerema

into' Student 'VALUES('8','Lee 48','123','male',' +','Jingan, Shanghai city'); INSERT into' Student 'VALUES('9','Zhang 39','111','male',' +','Shiyan, Hubei province'); INSERT into' Student 'VALUES('Ten','Lee 40','123','male',' +','Jingan, Shanghai city'); I. Querying 5~10 data MySQL Paging query: SELECT * FROM student limit 5, 10; Oracle Paging query: SELEC

Oracle experiences 1 -- oracle introduction @ basic SQL statement @ conditional query @ sort data theory and case studies1. Oracle IntroductionOracle is the first word for English translation of oracle (

1. Oracle Introduction Oracle is the first word for English translation of oracle (Oracle bone inscriptions) Unearthed from Yin.. Oracle is the world's largest supplier of information management software and services. It was founded in 1977 and is headquartered in Redwood sh

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By separatingSQL statement for local range data scanning Generally, it is more effective to put all components of an SQL statement that implements a function together. However, in a few cases, the SQL separation method is more effective. This situation mainly exists in that when you query two tables with a 1: M relationship, the data used to filter the condition

SQL format execution sequence of oracle data structure and sequence number of SQL query processing, oraclesql I. execution sequence of SQL format FROM-> WHERE-> group by-> HAVING-> SELECT-> ORDER 1. The from clause assembles data from different data sources; 2. The where cl

Usage scenarios:For example, you need to query all student numbers with scores greater than 95, separated by commas into a string, from the Student score table.To prepare the test data:CREATE TABLE score (ID int,score int)INSERT into score values (1,90)INSERT into score values (2,96)INSERT into score values (3,99)It is now necessary to query the result string "2,,3" with a single statement.The

condition record is met, and the final result is returned through the primary query. The filter execution plan will appear in the execution plan generated by the preceding statement, which also shows that this query is a special filtering operation (different from the traditional filtering operation, if traditional filtering operations become "Conditional filtering", such filtering operations can be called

Assume that you have a network ordering system based on Microsoft. NET, but the QC maintenance system still uses an old Oracle database application. If your customer places an order such as product replacement during the warranty period, the order will not be charged. In this case, you need to obtain real-time query results from the Oracle database. By establishi

DESC) T1) T2Order by primary key ASC For example, to retrieve 10 or 20 records from the table sys_option (primary key: sys_id), the statement is as follows:Select *From (select top 20 *From (select top 29 * From sys_option order by sys_id DESC) T1) T2Order by sys_id ASC Oralce database --------------------------------------------------------------------------------Retrieve N records from the M records in the database tableSelect *From (select rownum R, T1. * from table name T1 where rownum W

Advanced query and difficulties of Oracle and Mysql SQLMysql query Yang Kai exclusive Channel OracleSQL 1. Connection query 1. Internal Connection is used to return all records that meet the connection conditions. By default, if no join operator is specified during connection query