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 Related Questions Rename is a permanent name given to a table or column whereas Alias is a temporary name given to a table or column which do not exist once the SQL statement is executed. Latest Answer : Rename means give the new name to existed objects alise is use to refrence to objects ... A table can have only one PRIMARY KEY whereas there can be any number of UNIQUE keys. The columns that compose PK are automatically define NOT NULL, whereas a column that compose a UNIQUE is not automatically Latest Answer : Primay Key Unique key----------- ... '' Should be used before '%'. Latest Answer : select * from emp where instr('ename','%')!=0 ... SELECT * FROM empWhere emp_no+' '=12345;i.e you have to concatenate the column name with space within codes in the where condition.SELECT /*+ FULL(a) */ ename, emp_no from empwhere emp_no=1234;i.e Latest Answer : Its so distressing that no body could provide a better answer than a novice like me.In the where clause change the order of conditions in such a way that:Â 5 = value cond1 & value =5or value + 1 = 5 ... It is a column that is not an actual column in the table.eg USER, UID, SYSDATE, ROWNUM, ROWID, NULL, AND LEVEL. Latest Answer : Pseudo columns is not actula column in the table. it behaves like table columnwe can retivesv values of pseduo column but can not insert,update or delete value in that.has two data type 1. rowid 2. urowidrow id uniqely identify row in databaseEXM ... select level, min('col_name') from my_table where level = '&n' connect by prior ('col_name') Latest Answer : TO find out nth LOWEST value, e.g. salary from emp table without using ROWNUM & DESC/ASCSELECT DISTINCT (a.sal) FROM EMP A WHERE &N = (SELECT COUNT (DISTINCT (b.sal)) ... select level, max('col_name') from my_table where level = '&n' connect by prior ('col_name') >'col_name')group by level;Example:Given a table called emp with Latest Answer : SELECT MAX () FROM WHERE IN (SELECT TOP n FROM ORDER BY ASC)OR SELECT MIN () FROM WHERE IN (SELECT TOP n FROM ORDER BY DESC) ... What a SELECT FOR UPDATE cursor represent.[ANSWER]SELECT......FROM......FOR......UPDATE[OF column-reference][NOWAIT] The processing done in a fetch loop modifies the rows that have been retrieved by the cursor. A convenient way of modifying the rows is done by a method with two parts: the FOR UPDATE clause in the cursor declaration, WHERE CURRENT OF CLAUSE in an UPDATE or declaration statement. Data base trigger(DBT) fires when a DML operation is performed on a data base table. Form trigger(FT) Fires when user presses a key or navigates between fields on the screenCan be row level or statement Latest Answer : Database Trigger: We can't invoke a Form Trigger in DatabaseFrom Trigger: We can invoke a Database Trigger in Forms ... Merge Join :Oracle performs a join between two sets of row data using the mergejoin algorithm. The inputs are two separate sets of row data. Output isthe results of the join. Oracle reads rows Latest Answer : Merge Joins Sort merge joins can be used to join rows from two independent sources. Hash joins generally perform better than sort merge joins. On the other hand, sort merge joins can perform better than hash joins if both of the following conditions exist:The ...
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