Oracle

Oracle has id,a column to how to read the non-duplicate value of the slaughter, and with the ID to sort, please help?Solution:ID | A1 | X2 | Y3 | XNon-repeating value of column A: x, yBut when you sort by ID, the ID of X applies 1 or 3.Therefore,

1,nvl2 (a,b,c) --expression 1 is not NULL, returns expression 2, or null. Returns an expression of 3. Expression 2 is different from the expression 3 type, and expression 3 is converted to the type of expression 2.2,nvl (expression 1, Expression 2)--

ViewWhat is a viewA view is also known as a virtual table, which is a fictitious table, which is a logical representation of a set of data.The view corresponds to a SELECT statement, and the result set is given a name, which is the name of the

1, query can restore the point in timeSELECT * from V$sql where sql_text like '%update map_optcbl_point_70 set shape% '2. Data recovery to a new table, based on timestampCREATE TABLE newtable as SELECT * from oldtable as of timestamp to_timestamp ('

The 1.Oracle database is used to test three tables, EMP (Employee Information table), Dept (Departmental information table), Salgrade (Salary scale table), and their table structure is as follows:2. Calculate the annual salary (no bonus is

basic Syntax Multi-table QueryThe Cartesian product is implemented in SQL as a cross join. All connections will be made by Mr Sir as a temporary Cartesian product table. The Cartesian product is a concept in relational algebra that represents the

1 Index creation Syntax:CREATE UNIUQE | BITMAP INDEX .On .( | ASC | DESC, | ASC | DESC,...)Tablespace STORAGE LOGGING | NologgingCOMPUTE STATISTICSnocompress | CompressNosort | REVERSEPARTITION | GLOBAL partitionRelated instructions1) UNIQUE |

Here's how to modify it:Create pfile= '/tmp/init0924.ora ' from SPFile;Shutdown immediate--two nodes to stopStartup Nomout pfile= '/tmp/init0924.ora 'Create spfile= ' +data_mxsz/mxcn/spfilemxcn.ora ' from pfile= '/tmp/init0924.ora 'Srvctl Modify

Dapper is perfectly compatible with Oracle for executing stored procedures and returning resultsThis problem has plagued me for two days. When I used Dapper, I felt very cool. In particular, in combination with the new. net 4.0 dynamic, let me

Sort values in different columns based on conditions. Sometimes the ordering requirements are complex. For example, if a leader is more interested in employees with salaries between 1000 and 2000 yuan, the employees with salaries in this range must

Introduction to some basic login operations after Oracle 11g Release 2 is installed, oracle11g Oracle 11g is the latest database software released. Oracle 11g has more than 400 features. After 15 million hours of testing, the development workload

Convert a null value to an actual value. Create a test table: Create or replace view v asselect null as c1, null as c2, '1' AS c3, null as c4, '2' AS c5 FROM dualUNION allselect null as c1, null as c2, null as c3, '3' AS c4, '2' AS c5 FROM dual;

How to force oracle select and oracleselect In most cases, the built-in query optimization policy of the oracle database is still very successful, but occasionally, even if there is an index, full table scanning will be performed, you can refer to

Oracle Partition Outer Join thickening report, oracleouter Partition outer join converts sparse data into dense data. For example: With t as (select deptno, job, sum (sal) sum_sal from emp group by deptno, job), tt as (select distinct job from t)

Oracle mail, oracle Create or replace procedure PRC_sendmail (p_receiver VARCHAR2, -- mail recipient p_subject VARCHAR2, -- mail title p_message VARCHAR2 -- mail body) IS -- the following four variables should be assigned v_smtphost VARCHAR2 (30): =

OracleEBSR12-garbled characters when querying requests whose output format is "text" in Excel Oracle EBS R12-garbled query of requests whose output format is "text" in Excel Prerequisites for reproduction:Concurrent Programs whose output format is

MongoDB conventional backup policyMongoDB backup is actually a basic operation. Someone has been asking about it recently. It seems that many people are not familiar with it yet. In order to avoid repeated explanations, We will summarize a blog for

Oracle tablespace operations-- View the tablespace SELECT tablespace_name, file_id, file_name, round (bytes/(1024*1024), 0) | 'M' total_spaceFROM dba_data_filesORDER BY tablespace_name; -- create tablespace testlogging datafile

Oracle SQL tracking Select * from v $ sqlarea t where t. SQL _text like '% _ 070%' order by t. LAST_ACTIVE_TIME descSELECT * FROM v $ session st where st. SQL _ID = 'gabatezqjx0vc 'select t. hash_value, t. address from v $ sqlarea t where t. SQL

Auxiliary SQL statements for oracle Optimization -- Query the SQL statement that is being executed. SELECT the OSUSER computer logon identity, the PROGRAM where the PROGRAM initiates the request, the USERNAME used to log on to the system, SCHEMANAME,