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SQL In Oracle Interview Questions & Answers - Learning Mode

SQL In Oracle Interview Questions & Answers - Learning Mode

Structured Query Language (SQL) is the set of statements with which all programs and users access data in an Oracle database. Application programs and Oracle tools often allow users access to the database without using SQL directly, but these applications in turn must use SQL when executing the user's request. Oracle SQL provides an easy, elegant, performant architecture for accessing, defining, and maintaining data. In Oracle, SQL is divided into two basic groups: data definition language (DDL) or data manipulation language (DML).

Try SQL In Oracle Interview Questions & Answers - Exam Mode

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SQL In Oracle Interview Questions & Answers - Learning Mode
Try SQL In Oracle Interview Questions & Answers - Exam Mode
Question: Find out nth highest salary from emp table

For Eg:-
Enter value for n: 2
3700 Source:
Question: What is difference between SUBSTR and INSTR?

Answer: SUBSTR returns a specified portion of a string eg SUBSTR('BCDEF',4) output BCDE
INSTR provides character position in which a pattern is found in a string. eg INSTR('ABC-DC-F','-',2) output 7 (2nd occurence of '-') Source:
Question: Which is more faster - IN or EXISTS?

Answer: EXISTS is more faster than IN because EXISTS returns a Boolean value whereas IN returns a value. Source:
Question: Whet are the difference between primary key and foreign key?

Answer: 1)Primary key is unique key but foriegn key always refers to
primary key.

2) Primary keys enforce entity integrity by uniquely
identifying entity instances. Foreign keys enforce.

3)Primary key is unique
primary key is not NULL and

foreign key is NULL
foreign key reference as Primary key in another table.

4) primary key is used to identify a row and it doesnot allow
null values. It avoids duplication of rows.

whereas foreign key refers to a c Source:
Question: What is the maximum buffer size that can be specified using the DBMS_OUTPUT.ENABLE function?

Answer: 1,000,00 Source:
Question: What is an UTL_FILE.What are different procedures and functions associated with it?

Answer: UTL_FILE is a package that adds the ability to read and write to operating system files. Procedures associated with it are FCLOSE, FCLOSE_ALL and 5 procedures to
output data to a file PUT, PUT_LINE, NEW_LINE, PUTF, FFLUSH.PUT, FFLUSH.PUT_LINE,FFLUSH.NEW_LINE. Functions associated with it are FOPEN, ISOPEN. Source:
Question: Can the default values be assigned to actual parameters?

Answer: Yes Source:
Question: What is difference between a formal and an actual parameter?

Answer: The variables declared in the procedure and which are passed, as arguments are called actual, the parameters in the procedure declaration. Actual parameters contain the values that are passed to a procedure and receive results. Formal parameters are the placeholders for the values of actual parameters Source:
Question: Difference between an implicit & an explicit cursor.

Answer: PL/SQL declares a cursor implicitly for all SQL data manipulation statements, including quries that return only one row. However,queries that return more than one row you must declare an explicit cursor or use a cursor FOR loop. Explicit cursor is a cursor in which the cursor name is explicitly assigned to a SELECT statement via the CURSOR...IS statement. An implicit cursor is used for all SQL
statements Declare, Open, Fetch, Close. An explicit cursors are used to process multirow SELECT stat Source:
Question: What are various joins used while writing SUBQUERIES?

Answer: Self join-Its a join foreign key of a table references the same table. Outer Join--Its a join condition used where One can query all the rows of one of the tables in the join condition even though they don't satisfy the join condition.
Equi-join--Its a join condition that retrieves rows from one or more tables in which one or more columns in one table are equal to one or more columns in the second table. Source:
Question: What is difference between SQL and SQL*PLUS?

Answer: SQL*PLUS is a command line tool where as SQL and PL/SQL language interface and reporting tool. Its a command line tool that allows user to type SQL commands to be executed directly against an Oracle database. SQL is a language used to query the relational database(DML,DCL,DDL). SQL*PLUS commands are used to format query result, Set options, Edit SQL commands and PL/SQL. Source:
Question: Difference between procedure and function.

Answer: Functions are named PL/SQL blocks that return a value and can be called with arguments procedure a named block that can be called with parameter. A procedure all is a PL/SQL statement by itself, while a Function call is called as part of an expression. Source:
Question: Which datatype is used for storing graphics and images?

Answer: LONG RAW data type is used for storing BLOB's (binary large objects). Source:
Question: What should be the return type for a cursor variable.Can we use a scalar data type as return type?

Answer: The return type for a cursor must be a record type.It can be declared explicitly as a user-defined or %ROWTYPE can be used. eg TYPE t_studentsref IS REF CURSOR
RETURN students%ROWTYPE Source:
Question: What is the purpose of a cluster?

Answer: Oracle does not allow a user to specifically locate tables, since that is a part of the function of the RDBMS. However, for the purpose of increasing performance, oracle allows a developer to create a CLUSTER. A CLUSTER provides a means for storing data from different tables together for faster retrieval than if the table placement were left to the RDBMS. Source:
Question: Display the number value in Words?

Answer: SQL> select sal, (to_char(to_date(sal,'j'), 'jsp'))
from emp;
the output like,
--------- -----------------------------------------------------
800 eight hundred
1600 one thousand six hundred
1250 one thousand two hundred fifty
If you want to add some text like, Rs. Three Thousand only.
SQL> select sal "Salary ",
(' Rs. '|| (to_char(to_date(sal,'j'), 'Jsp'))|| ' on Source:
Question: Difference between database triggers and form triggers?

Answer: -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 screen
-Can be row level or statement level No distinction between row level and statement level.
-Can manipulate data stored in Oracle tables via SQL Can manipulate data in Oracle tables as well as variables in forms.
-Can be fired from any session executing the triggering DML statements. Can be fired only from the form Source:
Question: What are cursor attributes?

Answer: -%ROWCOUNT
-%ISOPEN Source:
Question: minvalue.sql Select the Nth lowest value from a table

Answer: select level, min('col_name') from my_table where level = '&n' connect by prior ('col_name') <
group by level;
Given a table called emp with the following columns:
-- id number
-- name varchar2(20)
-- sal number
-- For the second lowest salary:
-- select level, min(sal) from emp
-- where level=2
-- connect by prior sal < sal
-- group by level Source:
Question: How you will avoid duplicating records in a query?

Answer: By using DISTINCT Source:

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Latest 20 Questions
An offer which is open for acceptance over a period of time is: (a) Cross Offer (b) Counter Offer (c) Standing Offer (d) Implied Offer
Specific offer can be communicated to__________ (a) All the parties of contract (b) General public in universe (c) Specific person (d) None of the above
_________ amounts to rejection of the original offer. (a) Cross offer (b) Special offer (c) Standing offer (d) Counter offer
A advertises to sell his old car by advertising in a newspaper. This offer is caleed: (a) General Offer (b) Special Offer (c) Continuing Offer (d) None of the above
In case a counter offer is made, the original offer stands: (a) Rejected (b) Accepted automatically (c) Accepted subject to certain modifications and variations (d) None of the above
In case of unenforceable contract having some technical defect, parties (a) Can sue upon it (b) Cannot sue upon it (c) Should consider it to be illegal (d) None of the above
If entire specified goods is perished before entering into contract of sale, the contract is (a) Valid (b) Void (c) Voidable (d) Cancelled
______________ contracts are also caled contracts with executed consideration. (a) Unilateral (b) Completed (c) Bilateral (d) Executory
A offers B to supply books @ Rs 100 each but B accepts the same with condition of 10% discount. This is a case of (a) Counter Offer (b) Cross Offer (c) Specific Offer (d) General Offer
_____________ is a game of chance. (a) Conditional Contract (b) Contingent Contract (c) Wagering Contract (d) Quasi Contract
There is no binding contract in case of _______ as one's offer cannot be constructed as acceptance (a) Cross Offer (b) Standing Offer (c) Counter Offer (d) Special Offer
An offer is made with an intention to have negotiation from other party. This type of offer is: (a) Invitation to offer (b) Valid offer (c) Voidable (d) None of the above
When an offer is made to the world at large, it is ____________ offer. (a) Counter (b) Special (c) General (d) None of the above
Implied contract even if not in writing or express words is perfectly _______________ if all the conditions are satisfied:- (a) Void (b) Voidable (c) Valid (d) Illegal
A specific offer can be accepted by ___________. (a) Any person (b) Any friend to offeror (c) The person to whom it is made (d) Any friend of offeree
An agreement toput a fire on a person's car is a ______: (a) Legal (b) Voidable (c) Valid (d) Illegal
"Holiday Packages" announced as an advertisement are an example of _________: (a) Offer (b) Counter Offer (c) Invitation to Offer (d) None of the above
A match fixing contract between a player and a broker is a: (a) Valid Contract (b) Unenforceable Contract (c) Void Contract (d) Illegal Contract
When a bookseller sells a book on cash payment then it is called as ___________: (a) Unilateral Contract (b) Bilateral Contract (c) Executed Contract (d) Executory Contract
____________ agreements are created by situation: (a) Written (b) Oral (c) Void (d) Implied
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