Oracle

UNIONThe purpose of the directive is to have twoSQLThe result of the statement is merged together,You can view the results of the query you want.For example:SELECT Date from Store_informationUNIONSELECT Date from Internet_salesNote: Unionin use,two

Operator Description = Equal <> or! = Not equal Less than > Greater than Less than or equal >= Greater than or equal

1. Initial data:Sql> select * from A; ID NAME--------------------------------------------1 1sql> select * from B; ID NAME--------------------------------------------1 2

To start Oracle snooping:Su-oracle>lsnrctl Status View state>lsnrctl startOracle Startup EM:Emctl start Dbconsole Launch the EM console service, you need to set the ORACLE_SID environment variable before useEmctl Stop Dbconsole stops the EM console

1. The first step,First look at the storage path of the variable space--View Tablespace file pathSelect Tablespace_name,file_id,bytes/1024/1024,file_name From Dba_data_files order by file_id;2. Execute create temporal tablespace statement      

The physical structure of Oracle includes: parameter files, control files, data files, redo log files, archive files, password file composition.1.1 Parameter fileIncludes a number of settings that affect the capabilities of the Oracle DB instance,

1. Distinct usage:SELECT distiNCT a.name, a.student_id, a.sex from TABLE STUDENTThis SQL statement is from the Student table query name, school number, gender, but distinct query rule is as long as there is a difference, is eligible.Example: source

Level1 Level2 Level3 ... Record 1 Record 1 Record 1 ... Record 2 ... Record 3 ... Record 2 Record 1 ... Record 2 ...

First step, on the cmd command line, enter sqlplus or Open command window directly in PlsqlStep two, follow the prompts to enter the user name and password1. View processes and Sessions parametersSql> Show parameter Processes NAME

Object statistics Describe how data is stored in a database, and the query optimizer uses these statistics to make the right decisions. There are three types of object statistics in Oracle: Table statistics, column statistics, and index statistics.

The first time to install Oracle yourself, before the Oracle installation configuration is not in the past, finally fix, summed up.1. Install oracle10g server side2, install oracle10g client. The server side and client are not necessarily installed

This article lists several ways to export data from an Oracle table to a TXT file, currently only three methods are listed, if the subsequent discovery of better methods will continue to be added.1.plsqldev There is an option to put the table in

Differences between char, vchar, nchar, and nvchar, vcharnvcharChar and varchar are both between 1 and 8000 characters in length. The difference is that char is a fixed-length character data while varchar is a variable-length character data. The

Oracle wait event DFSlockhandle When performing a performance stress test, the test results cannot pass. The AWR Report of an hour on site is obtained and a large number of waiting events are found. The database is RAC and the version is 11.2.0.4.0.

OraclePL/SQL Composite data type Composite data types can be roughly divided into two types. The first type is record type, which is suitable for processing single row and multiple columns of data, a bit similar to VO in java; the first type is set

Rejected-ORA-01017 of tragedy: invalidusername/password; logondenied Error Oracle is not installed locally. oracle client and PL/SQL Developer are installed. To visualize the oracle database. Failed to log on when using PL/SQL login, error: ORA-01017

Handling Method for Rapid growth of oracle archive logs Oracle archive logs are generally generated by dml statements, so the increase speed should be too frequent by dml. First, query the generation of the following daily archives: Select trunc

How to retrieve the Oracle Password I believe most people will encounter such problems. I have also encountered such problems.First, he will ask you to enter the User name: you only need to enter connect/as sysdba, note that there is a space between

Oracle scheduled task # Su-oracleOracle> sqlplus "/as sysdba"SQL> exec dbms_scheduler.disable ('Monday _ window ');SQL> exec dbms_scheduler.disable ('tuesday _ window ');SQL> exec dbms_scheduler.disable ('wednesday _ window ');SQL> exec

Install Oracle11gR2 in RedhatLinux Official documents: http://docs.oracle.com/cd/E11882_01/nav/portal_11.htm 1: Basic Environment Redhat Enterprise Linux 6.132bit Memory: 1 GB Disk Space: 30 GB 2: Check the packages required for Oracle 11G. If the