oracle11g

问题 I have a query select * from tablename where rownum =1; This query is giving desired result but if i run select * from tablename where rownum=2; Then this query is giving null result. Any idea why? 回答1: The predicate WHERE rownum=2 can never be true because of the way ROWNUM is assigned. If there are 5 rows in the table, for example, the algorithm would go something like Retrieve the first row from the table. Assign it a rownum of 1. Check this rownum against the predicate, discard Retrieve

问题 This is my NM_CUST_APPLIANCE_HISTORY table ( for custoner_id=96 ) . Customer_id | Last_effective_date | Present_quentity --------------+---------------------+----------------- 96 | 2009-12-20 | 10 96 | 2014-11-18 | 12 96 | 2015-11-26 | 14 I execute my query to get start_date and immediate date of next row as a end_date for a single customer ( customer_id=96 ) . SELECT NM.CUSTOMER_ID customer_id, NM.LATEST_EFFECTIVE_DATE start_date, NVL ( CASE WHEN nm.LATEST_EFFECTIVE_DATE IS NULL THEN TO_DATE

问题 Code: set heading off set arraysize 1 set newpage 0 set pages 0 set feedback off set echo off set verify off spool 'c:\farmerList.csv' / select FIRSTNAME','LASTNAME','TRN','CELL','PARISH spool off The file is being saved to the directory, however it is saving the "select FIRSTNAME','LASTNAME','TRN','CELL','PARISH" and not the results of the query in csv format. What am i doing wrong? 回答1: Your select is incomplete as you don't have a from clause, but not sure if you've lost that in the copy

问题 I am using the queries to check how chr(0) behaves in regexp_like. CREATE TABLE t1(a char(10)); INSERT INTO t1 VALUES('0123456789'); SELECT CASE WHEN REGEXP_LIKE(a,CHR(0)) THEN 1 ELSE 0 END col, DUMP(a) FROM t1; The output I am getting like this - col dump(a) ----------- ----------------------------------- 1 Typ=96 Len=10: 48,49,50,51,52,53,54,55,56,57 I am totally confused, if there is no chr(0) as shown by the dump(a), how regexp_like is finding the chr(0) in the column and returning 1?

问题 I have a basic requirement of connecting an on premise Oracle database to Redshift. I need to use AWS Lambda to connect to both the databases using python. While I achieved connection to Redshift by exporting Linux libraries of psycopg2 , I am facing issues with the Oracle database. Below are the steps followed to try to connect to Oracle on premise DB : Installed cx_Oracle which came up with cx_Oracle.cpython-36m-x86_64-linux-gnu.so and psycopg2-2.7.4.dist-info Installed basic oracle client

问题 I am trying to perform update action in Visual Studio 2010 Ultimate with Windows form as the front end and Oracle 11g express as the back end. I am using C# to code this. private void update_student(string STUDENT_ID, string STUDENT_NAME, string STUDENT_ADDRESS) { con.Open(); String sql = "UPDATE STUDENT SET STUDENT_NAME = :STUDENT_NAME, STUDENT_ADDRESS= :STUDENT_ADDRESS WHERE STUDENT_ID= :STUDENT_ID"; OracleCommand query = new OracleCommand(sql, con); OracleParameter[] updatestud = new

问题 I have a table named student_info in my database.There are multiple columns out of which two columns store comma separated values class_id student marks ---------------------------------------------- 1 tom,jam,tim 55,65,75 2 rim,gum,ram 33,66,77 i want the output to be as follows class_id student marks ------------------------------------------------ 1 tom 55 1 tom 65 1 tom 75 1 jam 55 1 jam 65 1 jam 75 1 tim 55 1 tim 65 1 tim 75 my Query as below SELECT student_id,TRIM(REGEXP_SUBSTR(student,

问题 Is is possible to find out the datatype of a column of a cursor or variable within block without using system tables? While I understand that I can use the system tables to find out this information it would be a lot slower. Something like, declare my_column_data_type varchar2(30); begin my_column_data_type := all_tables.table_name%type; dbms_output.put_line(my_column_data_type); end; I can't find any way of doing it without resorting to dbms_sql , which would be overkill for my eventual

问题 I am getting the "Protocol Violation". I have an application running on RedHat Linux.The database and the application are co-resident on the machine. Oracle version used: Oracle 11g R2 (11.2.0.3.0) JDBC Driver used: 12.1.0.1 Java used: jdk1.7.0.65 32-bit I have come across many forums where this error has been pointed out to be a driver issue but in all those forums the oracle version used was higher and the driver version were older and changing the driver resolved the issue.But in my case

问题 Hi I coded a Library Management System in JSF 2.2 with using Netbeans 8.0.2 and Oracle 11g Express Edition. I have several pages named Books, Borrowers etc. and some tables named same in database. My problem is this: in Borrowers screen book ids are displayed. But I want to reach book's titles that have same id. Here is my code. public List<Borrower> getBorrowers()throws ClassNotFoundException,SQLException, InstantiationException, IllegalAccessException{ Class.forName("oracle.jdbc.driver