SQL Plus Interview Preparation Guide

SQL Plus guideline for job interview preparation. Explore list of SQL Plus frequently asked questions(FAQs) asked in number of SQL Plus interviews. Post your comments as your suggestions, questions and answers on any SQL Plus Interview Question or answer. Ask SQL Plus Question, your question will be answered by our fellow friends.

20 SQL Plus Questions and Answers:

1 :: Please Explain Connect by Prior?

Retrieves rows in hierarchical order.e.g. select empno, ename from emp where.

"connect by prior" is clause which is used in hierarchical queries.Example
select ename,empno,mgr,job
from emp
start with job='PRESIDENT'
connect by prior empno=mgr;

2 :: Explain ROWID?

ROWID is a pseudo column generated at the run time(during inserting value). Its a hexadecimal value which is unique identification for each record

3 :: Explain Explicit Cursor attributes?

%IS OPEN,%FOUND,%NOT FOUND,%ROW COUNT

4 :: Explain What is a database link?

Database Link is a named path through which a remote database can be accessed

5 :: Explain What is a corelated subquery?

Correlated subquery is the subquery, where the subquery has been executed for the every row processed by the parent statement.

7 :: What is a join in Oracle? Explain the different types of joins?

Join is a query which retrieves related columns or rows from multiple tables.Self Join - Joining the table with itself.Equi Join - Joining two tables by equating two common columns.Non-Equi Join - Joining two tables by equating two common columns.Outer Join - Joining two tables in such a way that query can also retrieve rows that do not have corresponding join value in the other table.

JOIN: Return rows when there is at least one match in both tables
LEFT JOIN: Return all rows from the left table, even if there are no matches in the right table
RIGHT JOIN: Return all rows from the right table, even if there are no matches in the left table
FULL JOIN: Return rows when there is a match in one of the tables

8 :: Explain What are the data types allowed in a table?

CHAR,
VARCHAR2,
NUMBER,
DATE,
RAW,
LONG and
LONG RAW.

9 :: Explain How do we replace a comma (,) with a blank in a select statement?

select empno||' '||ename from emp;

select replace (column name,',','') from table name.

10 :: Explain Can a view be updated/inserted/deleted?

if a view is update, deleted , or inserted wil the changes be refelected on the base table