RE: Basic SQL Interview Questions

ksrao — Tue, 31 Aug 2010 01:10:00 GMT

HI,
These questions are good.
The set of questions can be increased depending on the topic so that it can cover total SQL.

I found some more good [url=http://www.wiziq.com/online-tests/12589-oracle-sql-pl-sql-quiz]oracle sql interview questions[/url] for those who are preparing for SQL Interview.

Thanks
Kolla Sanjeeva Rao
OCP,Oracle 9i.

Basic SQL Interview Questions

Admin — Wed, 03 Dec 2008 15:29:39 GMT

What's SQL

SQL is an English like language consisting of commands to store, retrieve, maintain & regulate access to your database.

What's SQL*Plus

SQL*Plus is an application that recognizes & executes SQL commands & specialized SQL*Plus commands that can customize reports, provide help & edit facility & maintain system variables.

What's NVL

NVL : Null value function converts a null value to a non-null value for the purpose of evaluating an expression. Numeric Functions accept numeric I/P & return numeric values. They are MOD, SQRT, ROUND, TRUNC & POWER.

What's Date Functions

Date Functions are ADD_MONTHS, LAST_DAY, NEXT_DAY, MONTHS_BETWEEN & SYSDATE.

What's Character Functions

Character Functions are INITCAP, UPPER, LOWER, SUBSTR & LENGTH. Additional functions are GREATEST & LEAST. Group Functions returns results based upon groups of rows rather than one result per row, use group functions. They are AVG, COUNT, MAX, MIN & SUM.

What's TTITLE & BTITLE

TTITLE & BTITLE are commands to control report headings & footers.

What's COLUMN

COLUMN command define column headings & format data values.

What's BREAK

BREAK command clarify reports by suppressing repeated values, skipping lines & allowing for controlled break points.

What's COMPUTE

command control computations on subsets created by the BREAK command.

What's SET

SET command changes the system variables affecting the report environment.

What's SPOOL

SPOOL command creates a print file of the report.

What's JOIN

JOIN is the form of SELECT command that combines info from two or more tables.
Types of Joins are Simple (Equijoin & Non-Equijoin), Outer & Self join.
Equijoin returns rows from two or more tables joined together based upon a equality condition in the WHERE clause.
Non-Equijoin returns rows from two or more tables based upon a relationship other than the equality condition in the WHERE clause. Outer Join combines two or more tables returning those rows from one table that have no direct match in the other table. Self Join joins a table to itself as though it were two separate tables.

What's Union

Union is the product of two or more tables.

What's Intersect

Intersect is the product of two tables listing only the matching rows.

What's Minus

Minus is the product of two tables listing only the non-matching rows.

What is a Correlated Subquery ?

Correlated Subquery is a subquery that is evaluated once for each row processed by the parent statement. Parent statement can be Select, Update or Delete. Use CRSQ to answer multipart questions whose answer depends on the value in each row processed by parent statement.

What are Multiple columns ?

Multiple columns can be returned from a Nested Subquery.

What are Sequences ?

Sequences are used for generating sequence numbers without any overhead of locking. Drawback is that after generating a sequence number if the transaction is rolled back, then that sequence number is lost.

What are Synonyms ?

Synonyms is the alias name for table, views, sequences & procedures and are created for reasons of Security and Convenience. Two levels are Public - created by DBA & accessible to all the users. Private - Accessible to creator only. Advantages are referencing without specifying the owner and Flexibility to customize a more meaningful naming convention.

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RE: Basic SQL Interview Questions

Basic SQL Interview Questions