sql query tuning techniques in oracle

Tags: ora-00942After Oracle creates a new user, the client executes the SQL query with the following error message:Execute the query statement as follows:SELECT * from Sm_sales_order;ORA-00942: Table or view does not existCreate a new user and specify tablespace and temp table spaceCREATE USER xxx identified by xxxxDEF

Tags: style blog http io ar os SP data onThere is a connect by clause in Oracle. is used for hierarchical queries. is a recursive query. Where the syntax is as follows:SELECT ... From notes:1. CONDITIONAL-1 Condition: The filter condition in SQL,2.conditional-2 condition: Is the definitive statement of the root node, and the condition from which to start.3. CONDI

Tags: using ar sp data div art on BS sizePaged query statements that are used in different databases:Current page: CurrentPagePage Size: pagesize1. Oracle DatabaseSELECT * FROM (select A.*,rownum rn from (query_sql) A) where Rn Note: query_sql is a query SQL statement.OrSELECT * FROM (select RowNum rn,id from TABLENAME

I. Overview of SQL　　Origins in the standard no longer repeat, mainly divided into ddl,dml,dclFor an introduction, refer to MySQL section : http://www.cnblogs.com/jiangbei/p/6696202.html　　Objective of this section:by studying this chapter, you will be able to: enumerate the functions of the SQL SELECT statement.　　Executes a simple SELECT statement. SQL languagedif

The author of the article gave great help to elder withered flourish, in order to express my gratitude.This applies to the Oracle DB version number, Oracle 10g, or later.It is important to say that this view is one of the AWRSQRPT reports is not in. is the filter_predicates column.SELECT Plan_hash_value,To_char (Rawtohex (child_address)), To_number (child_number), ID, Lpad (", DEPTH) | | Operation operation

This article is a detailed analysis of the implementation of the Oracle Query and deletion job SQL, the need for a friend under the reference nbsp; Query and delete duplicate records of SQL statements 1, find redundant records in a table, duplicate records are based on

After reading this blog post, Oracle, MYSQL, SQL Server data paging query, in accordance with the company's Regionres table madePaging query statements for SQL Server:SELECT DISTINCT TOP -rr.id asID, Rr.strname asname, Rr.ntype asRes_type, Rr.nregid asregion_id, Rr.strchann

First look at how SQL writesSelect * from ( Select A.*, ROWNUM rn from (lowest query statement ) A wherelt; = #{endcol} ) where gt; #{startcol}Note: Of course we also need select COUNT (*) the lowest query statement to get the total number of result sets. And then

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SelectTest1.*,test2.* fromTest1Inner JoinTest2 onTest1.1=Test2.1//Internal connection Select test1.*,test2.* fromTest1 Right outer JoinTest2 onTest1.1=Test2.1//Outer connection 1.1 right outer connection, the display of the Test2 table data is the main, the left side of the table without restrictions usually omitted outer Selecttest1.*,test2.* fromTest1 Left outer JoinTest2 onTest1.1=Test2.1//1.2 left outer connection Selecttest1.*,test2.* fromTest1 Full outer JoinTest2 onTest1.1=Test2.1//1.3

1. Use the top command to see the SPID numbers with the most productive resources first2. Query the current time-consuming session ID, user name, Sqlid, etc.: Select sid,serial#,machine,username,program,sql_hash_value,sql_id, To_char (Logon_time, ' Yyyy/mm/dd hh24:mi:ss ') as Login_time from V$session where paddr in (select addr from v$process where spid in (' 5648612 ', ' 256523 '));3. If the previous step sql_id or Hash_value is not empty, V$sqlarea

Label:1.View server-side encodingSelect Userenv (' language ') from dual;The result I actually found was: American_america. Al32utf82.EXECUTE statement SELECT * FROM V$nls_parametersSee if the value in the parameter item in the first row is the same as the one obtained in the first step for nls_language.If not, you need to set the environment variable.Otherwise, the encoding used by the Plsql client is inconsistent with the server-side encoding and garbled when inserting Chinese.3.Setting enviro