Oracle

select * from test; No Time Name 1001 20141226 Zhangsan 1001 20141227 Lisi 1002 20141228 Wangwu 1002 20141229 Zhaoliu

Defined the Recovery Manager (RMAN) retention policy to RecoveryWindow of 7 days by executing the following command:Rman> CONFIGURE RETENTION POLICY to RECOVERY windows of 7 days;When a backup was performed, what would was the status of this backup

References organized from: http://docs.oracle.com/cd/B19306_01/network.102/b14266/admusers.htm#i1006856Just pick dry words!!!One user management1. Create userCreate user DylanIdentified by 123Default Tablespace users--Specify table spaceQuota 100m

Date functionSysdate-- Current system Time Select from dual;EXTRACT-- get Current year Select Extract (year from from-- years Select Extract ( month from from– month Select Extract (Day from- - DayTo_date--Convert a string to a dateSELECTTo_date (

Union/union All and setINTERSECT intersectionMinus difference SetWe know that group by enhanced http://www.cnblogs.com/liuwt365/p/4181256.htmlGROUP BY rollup (A, B)=Group by A, b+GROUP by a+GROUP BY NULLSo we should write the SQL statement should be:

--Create a sequence:CREATE SEQUENCE Seq_grelation--use unified prefix to make it easy to manageINCREMENT by 1-the self-increment step is set here to 1Start with 1--count start here set to 1Nomaxvalue--No maximum option is set maxvalue|

One, the string functionLENGTH (CHAR):SELECT LENGTH ('abc def GH' from dual; -- gets the length of the string that contains the space result:CONCAT (CHAR1,CHAR2)SELECTCONCAT ('ABC','def') fromDual--Connect two stringsResults:'abcdef'SELECT

The benefit of the oracle10g Recycle Bin is that when a table is mistakenly deleted, there is a mechanism for recovery, but if you do not need to use this feature, you can use the command to close1. Turn off or turn on the Recycle Bin functionALTER

In Oracle, sometimes the sort keyword is seen in the execution plan, and some people think that sort is done, but not necessarily. You can experiment with the following methods:drop table test Purge;CREATE TABLE Test as SELECT * from

first, how to effectively use the data dictionary  Oracle's data dictionary is one of the most important parts of a database, which is generated as a result of the database, and changes as the database changes, reflecting some of the tables and

14th Chapter Advanced Sub-query1. Sub-querySubquery (inner query) executes before the main query executesMain query (outer query) uses the results of a subquerySELECTselect_listFromtableWHEREexpr operator (SELECT select_listFrom table);Question:

[SQL]View Plaincopyprint? Sql> Show Parameter Open_cursors -the maximum number of cursor (cursors) that can be opened at the same time per session NAME TYPE VALUE ------------------------------------ ----------- ---------------------------

1, first, introduce the TO_CHAR functionTo_char is to convert a date or number to a string and cannot specify a string length.Use the TO_CHAR function to process the date:To_char (number, ' format ') For example: To_char (Salary, ' $99,999.99 ')Use

A media failure has occurred. This have resulted in all the MembeRs of the next hop log group being rendered inaccessible to the log WRiter process (LGWR) at a log switch. How does this failure affect thE Operational database?A. The database

A potential customer asked my about porting she application from Oracle Database to MySQL.I always try-to-start with the ' why ' (a dear friend bought me this book, Recommended:http://www.amazon.com/start-why-lead ers-inspire-everyone/dp/1591846447).

You have set some of the initialization parameters as:db_block_size=8kbSga_max_size=2gbSga_target =0shared_pool_size=120mbdb_chche_size=896mbStream_pool_size=0large_pool_size=110mbWhich statements is correct? (Choose).A. You can not set a value for

After the installation of Oracle, it is usually found that there are 2 system-level accounts can log in, but never considered the difference between the 2 accounts, and then learned from a teacher that the difference is recorded.SYS account login,

Specified Date query data base 1. First, introduce the to_char function. TO_CHAR converts a date or number to a string and cannot specify the string length.Use the TO_CHAR function to process the date:TO_CHAR (number, 'format') for example:

Oracle (11) string function, oracle string I. String Functions LENGTH (char1, char2) Select length ('abc def gh') FROM dual; -- get the LENGTH of the string, containing spaces. Result: 10   CONCAT (char1, char2) Select concat ('abc', 'def ') FROM

Impdp terminate ORA-7445 due to fatal errors [kpodpals]It was difficult to successfully export all the data to the user the day before yesterday. Today, the user told me that the exported data could not be imported. First, ask the user for any error