Oracle

The syntax structure of the Decode function is as follows: Copy codeThe Code is as follows:Decode (expression, search_1, result_1)Decode (expression, search_1, result_1, search_2, result_2)Decode (expression, search_1, result_1, search_2, result_2,..

Table query: Merge query: Use the union keyword to remove duplicate rows that meet the condition.Copy codeThe Code is as follows:Select ename, sal, job from emp where sal> 2500 union select ename, sal, job from emp where job = 'manager '; Union all

Requirement:Currently, due to the large number of transaction records in the business system, some supervisors often need to see all the records, but do not want to scroll. They can see all the records at a glance, so I thought of the form of String

1. If the Console is not installed on the database machine or the network service name is not configured using the Console.You can log on to the idle process on the server by running the command sqlplus sys/sys as sysdba. See step 4.2. If the

In the where clause of Oracle SQL, input the character type parameter '19th-August 08 ', so that it can be directly compared with the date type or converted to the same date type comparison.If the entered character format is the same as

1 \ flash the table back to a certain time point:Enable the row movement function before the flash back operationSQL code Alter table emp enable row movement;Execute the flash back statement:SQL codeFlashback table emp to timestamp to_timestamp ('000

After finishing the project yesterday, I asked the test to test it. The test said that paging query does not seem to work. After Turning to page 4th, the data results will be the same.At that time, I was puzzled. It was impossible. The paging

Applicability:When oracle sorts the query results, the column to be sorted has a null value, and the NULL value must be specified at the beginning or end of the column.Keywords: Nulls First; Nulls LastDefault Value: the default value of null is the

When the data in the table is not required, Delete the data and release the occupied space. To Delete the data in the table, use the Delete statement or the Truncate statement.I. delete statements(1) conditional DeletionSyntax format: delete [from]

Today, the virtual machine is configured with an ip address, so that the virtual machine and the host are in the same network segment, and then webservice is used successfully, but a new problem arises, and oracle cannot be connected.I found that

In this article, the B-tree (B-tree) Hash k-d tree (k-d tree) Point Quadtree (Point Quadtree) This article describes the structure of Oracle indexes. You can understand the underlying data structure of Oracle indexes to better understand the

Principle 1: Pay attention to the connection sequence in the WHERE clause:ORACLE uses the bottom-up sequence to parse the WHERE clause. According to this principle, the join between tables must be written before other WHERE conditions. The

In addition, some of the differences they listed are quite meaningful. Some may be due to their own identity as a MySQL DBA, and some may be confused about Oracle. however, in general, the list of Baron Schwartz can help you understand the

Author: peace. zhaoExample of cursor if andCreate or replace procedure peace_ifIsCursor var_c is select * from grade;BeginFor temp in var_c loopIf temp. course_name = 'OS' thenDbms_output.put_line ('stu _ name = '| temp. stu_name );Elsif temp.

Let's sum up and answer these two common questions that most netizens are concerned about.Differences between in and existFrom the perspective of SQL programming, in is intuitive, and exists is not intuitive. There is one more select,In can be used

The SecureFile function is a completely re-designed implementation of the large object (LOB) storage format in oracle 11g. The original LOB storage format is now called BASIXFILE, and it is still the default storage method, however, the SECURFILE

I. IntroductionSuper Large systems have the following features:1. Generally, the number of users processed exceeds 1 million, and the number of users processed exceeds 10 million. The data volume of the database generally exceeds 1 TB;2. The system

Q:I am working with Oracle database 8.1.7 and I have written a JAVA code to update the table which contains one BLOB field.I am using updateBinaryStream method of resultset to update the BLOB field but it is failing after giving following

The ORACLE tutorial is: Oracle acquires TimesTen to improve database software performance. Oracle announced in June 9 that it had agreed to acquire TimesTen, a private software company whose products can improve the performance of database

The ORACLE tutorial is: Analysis and Solution 2 of common ORACLE error codes.--------------------------------------------------------------------------------P align = "JUSTIFY"> ORA-01578: Oracle data block upted (file # num, block # num)Cause: When