SQL SERVER – 2008 – Interview Questions and Answers – Part 2

SQL Server Interview Questions and Answers
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SQL SERVER – 2008 – Interview Questions and Answers Complete List Download

1) General Questions of SQL SERVER

What is Cursor?

Cursor is a database object used by applications to manipulate data in a set on a row-by-row basis, instead of the typical SQL commands that operate on all the rows in the set at one time.

In order to work with a cursor we need to perform some steps in the following order:

  • Declare cursor
  • Open cursor
  • Fetch row from the cursor
  • Process fetched row
  • Close cursor
  • Deallocate cursor (Read More Here)

What is Collation?

Collation refers to a set of rules that determine how data is sorted and compared. Character data is sorted using rules that define the correct character sequence, with options for specifying case sensitivity, accent marks, kana character types and character width. (Read More Here)

What is Difference between Function and Stored Procedure?

UDF can be used in the SQL statements anywhere in the WHERE/HAVING/SELECT section where as Stored procedures cannot be. UDFs that return tables can be treated as another rowset. This can be used in JOINs with other tables. Inline UDF’s can be thought of as views that take parameters and can be used in JOINs and other Rowset operations.

What is sub-query? Explain properties of sub-query?

Sub-queries are often referred to as sub-selects, as they allow a SELECT statement to be executed arbitrarily within the body of another SQL statement. A sub-query is executed by enclosing it in a set of parentheses. Sub-queries are generally used to return a single row as an atomic value, though they may be used to compare values against multiple rows with the IN keyword.

A subquery is a SELECT statement that is nested within another T-SQL statement. A subquery SELECT statement if executed independently of the T-SQL statement, in which it is nested, will return a resultset. Meaning a subquery SELECT statement can standalone and is not depended on the statement in which it is nested. A subquery SELECT statement can return any number of values, and can be found in, the column list of a SELECT statement, a FROM, GROUP BY, HAVING, and/or ORDER BY clauses of a T-SQL statement. A Subquery can also be used as a parameter to a function call. Basically a subquery can be used anywhere an expression can be used. (Read More Here)

What are different Types of Join?

Cross Join

A cross join that does not have a WHERE clause produces the Cartesian product of the tables involved in the join. The size of a Cartesian product result set is the number of rows in the first table multiplied by the number of rows in the second table. The common example is when company wants to combine each product with a pricing table to analyze each product at each price.

Inner Join

A join that displays only the rows that have a match in both joined tables is known as inner Join.  This is the default type of join in the Query and View Designer.

Outer Join

A join that includes rows even if they do not have related rows in the joined table is an Outer Join.  You can create three different outer join to specify the unmatched rows to be included:

  • Left Outer Join: In Left Outer Join all rows in the first-named table i.e. “left” table, which appears leftmost in the JOIN clause are included. Unmatched rows in the right table do not appear.

  • Right Outer Join: In Right Outer Join all rows in the second-named table i.e. “right” table, which appears rightmost in the JOIN clause are included. Unmatched rows in the left table are not included.

  • Full Outer Join: In Full Outer Join all rows in all joined tables are included, whether they are matched or not.

Self Join

This is a particular case when one table joins to itself, with one or two aliases to avoid confusion. A self join can be of any type, as long as the joined tables are the same. A self join is rather unique in that it involves a relationship with only one table. The common example is when company has a hierarchal reporting structure whereby one member of staff reports to another. Self Join can be Outer Join or Inner Join. (Read More Here)

What are primary keys and foreign keys?

Primary keys are the unique identifiers for each row. They must contain unique values and cannot be null. Due to their importance in relational databases, Primary keys are the most fundamental of all keys and constraints. A table can have only one Primary key.

Foreign keys are both a method of ensuring data integrity and a manifestation of the relationship between tables.

What is User Defined Functions? What kind of User-Defined Functions can be created?

User-Defined Functions allow defining its own T-SQL functions that can accept 0 or more parameters and return a single scalar data value or a table data type.

Different Kinds of User-Defined Functions created are:

Scalar User-Defined Function

A Scalar user-defined function returns one of the scalar data types. Text, ntext, image and timestamp data types are not supported. These are the type of user-defined functions that most developers are used to in other programming languages. You pass in 0 to many parameters and you get a return value.

Inline Table-Value User-Defined Function

An Inline Table-Value user-defined function returns a table data type and is an exceptional alternative to a view as the user-defined function can pass parameters into a T-SQL select command and in essence provide us with a parameterized, non-updateable view of the underlying tables.

Multi-statement Table-Value User-Defined Function

A Multi-Statement Table-Value user-defined function returns a table and is also an exceptional alternative to a view as the function can support multiple T-SQL statements to build the final result where the view is limited to a single SELECT statement. Also, the ability to pass parameters into a TSQL select command or a group of them gives us the capability to in essence create a parameterized, non-updateable view of the data in the underlying tables. Within the create function command you must define the table structure that is being returned. After creating this type of user-defined function, It can be used in the FROM clause of a T-SQL command unlike the behavior found when using a stored procedure which can also return record sets. (Read Here For Example)

What is Identity?

Identity (or AutoNumber) is a column that automatically generates numeric values. A start and increment value can be set, but most DBA leave these at 1. A GUID column also generates numbers; the value of this cannot be controlled. Identity/GUID columns do not need to be indexed.

What is DataWarehousing?

  • Subject-oriented, meaning that the data in the database is organized so that all the data elements relating to the same real-world event or object are linked together;
  • Time-variant, meaning that the changes to the data in the database are tracked and recorded so that reports can be produced showing changes over time;
  • Non-volatile, meaning that data in the database is never over-written or deleted, once committed, the data is static, read-only, but retained for future reporting.
  • Integrated, meaning that the database contains data from most or all of an organization’s operational applications, and that this data is made consistent.

© Copyright 2000-2009 Pinal Dave. All Rights Reserved. SQLAuthority.com

Reference : Pinal Dave (http://blog.SQLAuthority.com)

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40 thoughts on “SQL SERVER – 2008 – Interview Questions and Answers – Part 2

  1. Hi Pinal Dev,

    Nice work plz keep it up continue.

    I looking for change my job i have 2yrs exp in IT/software developement. Please send me new and typicall Q&A that might be ask in interviews.

    Thanks

    Ajay

    Like

  2. Sir,

    First of all, i would like to thank you for this amazing website. It is such a comprehensive resource for Sql server.
    Thanks.

    Just simple question, why this topic goes with title ‘sql server 2008′ Interview questions?
    I didn’t come across any question which is related specifically to SQL Server 2008. They all are very general questions related to SQL server irrespective of their Version.

    Thanks,

    Like

  3. Hi Mudit,

    This are beginning questions. I have many part of this interview series. In last three part I will be talking about SQL Server 2008 only.

    My intention was to provide complete SQL Server solutions and with keeping the same goal in mind this series has started.

    Please continue reading blog and next parts of SQL Server interview questions and answers.

    Regards,
    Pinal

    Like

  4. Hie Pinal,

    As per your last comment, this are just beginning questions so please let me know where do i find many other part of this interview series. Thanks..

    Like

  5. Hi ,

    I am new to SQL SERVER. I am seriouly learning. I am trying to install adveture work database(sql server 2005) but i can’t.

    Can someone please send the link for free download.

    And if any one have any practice questions on joins please send me & help me for my oncomming life.

    Like

  6. Dear mr. pinal
    recently in my search for such a strong web site to solve my problems in sql server (specialy in data transfer from branches of a company) i founded your site.
    thank you for such a web site .
    i will be happy to have some guidelines for my problems in best way to have a strategic paln for data transfer through dialup lines ….
    B.rgds rostami

    Like

  7. Hi Pinal,

    Thank you very much for the informative questions.
    I wanted to find whether there is any series for Sql Server 2005 too?

    Thanks,
    Gautam

    Like

  8. Hi

    Nice to see such websites. I am web developer working on sql server. Sir I want script which can return values based on different conditions for each column in that resultset.

    Like

  9. Hi All,

    I have same question from http://p2p.wrox.com/book-beginning-database-design/75764-many-many-self-joins.html

    Table: Employees
    empid :: empname
    1 :: adam
    2 :: bob
    3 :: candy
    4 :: doug
    5 :: earl
    6 :: fran

    Table: Subordinates
    empid :: sub_empid
    3 :: 2
    3 :: 5
    2 :: 1
    2 :: 4
    5 :: 6

    That is:
    — Candy manages both Bob and Earl
    — Bob manages both Adam and Doug
    — Earl manages Fran

    How to query out whole company’s structure but not just two level manager-employee by apply self-join?

    Like

    • What exactly do you want? Just the employee names of manager and subordinate?

      WITH
      Employees(empid, empname)
      AS
      (
      SELECT 1, ‘adam’ UNION ALL
      SELECT 2, ‘bob’ UNION ALL
      SELECT 3, ‘candy’ UNION ALL
      SELECT 4, ‘doug’ UNION ALL
      SELECT 5, ‘earl’ UNION ALL
      SELECT 6, ‘fran’
      ),
      Subordinates(empid, sub_empid)
      AS
      (
      SELECT 3, 2 UNION ALL
      SELECT 3, 5 UNION ALL
      SELECT 2, 1 UNION ALL
      SELECT 2, 4 UNION ALL
      SELECT 5, 6
      )
      SELECT
      Emp_1.empname Manager,
      Emp_2.empname Subordinate
      FROM
      Employees Emp_1,
      Employees Emp_2,
      Subordinates
      WHERE
      Emp_1.empid = Subordinates.empid
      AND Emp_2.empid = Subordinates.sub_empid
      ORDER BY
      Emp_1.empname;

      Like

  10. Pingback: SQL SERVER – Interview Questions & Answers Needs Your Help Journey to SQL Authority with Pinal Dave

  11. If we are applying selfjoin then:

    create table #emp_temp
    (
    empid int,
    subid int,
    name varchar(20)
    )

    insert into #emp_temp
    select 1,2,’adam’
    union all
    select 2,3,’bob’
    union all
    select 3,null,’candy’
    union all
    select 4,2,’doug’
    union all
    select 5,3,’earl’
    union all
    select 6,5,’fran’

    select m.name Manager, s.name Subordinate
    from #emp_temp m join #emp_temp s on s.subid=m.empid

    Like

  12. Pingback: SQL SERVER – The Self Join – Inner Join and Outer Join Journey to SQL Authority with Pinal Dave

  13. Hello Pinal:
    I have a question about blogs because I want to start one.
    Your help will be very much appreciated if you can please let me what I will need to do it? Thank you

    Like

  14. This is one of the best article for SQL server.
    Any one can easily understand all the fundamentals of SQL server.
    Thanks.

    Nilay Shah

    Like

  15. hi sir,

    i am working with sqlserver2008
    i got one problem
    in joins

    select *from EMPP
    select *from Dept
    ——————————-
    select EMPP.Eno,EMPP.Ename,Dept.DeptNo
    from EMPP innor join Dept
    on EMPP.Eno=Dept.DNo
    —————————————————

    Msg 4104, Level 16, State 1, Line 4
    The multi-part identifier “EMPP.Eno” could not be bound.
    Msg 4104, Level 16, State 1, Line 2
    The multi-part identifier “EMPP.Eno” could not be bound.
    Msg 4104, Level 16, State 1, Line 2
    The multi-part identifier “EMPP.Ename” could not be bound.

    Plz Help me, how to avoid this Error

    Like

  16. Hi

    IN the question for difference between stored procedure and functions. Do user defined functions compile and has a plan. if not then is it wise to say that, we can use functions also in places where the SQL engine does not need to store the plan and where a logic needs to be called 1000 times but there is no need to store the plan and take procedure cache space.

    Like

  17. hello sir,

    really it is a good site to all type of exp person could u send me some of the important questions for my further interview

    Looking forward for your replay sir

    thanking you
    nikesh

    Like

  18. The best resources one can ever find related to SQL Server.
    Thank you so much for sharing the valuable information. Keep doing the good deeds.

    Like

  19. Hi Pinal

    I am Deepthi..This is really a very informative site..It gives good knowledge of sql server…

    I have a small doubt..Can you just tell me whats the difference between a view and user defined function..in which situations each of them will be used…

    Like

  20. Hi Pinal,

    Thanks for everything. I appreciate your effort to provide us everything simple and accurate.
    I have two questions about cursor.
    Mostly we are asked to avoid cursors, is there any situation when we must have to use a cursor? and what is the most important benifit using a cursor?

    Like

  21. Hi Pinal,
    I am working in an mnc. and my main role release Engineer and i need to do website and ssrs script deployements. Can u pls suggest me what all concepts i need to study for upcoming interviews for the same role.

    Thanks
    Regards,
    Sneha

    Like

  22. Pingback: SQL SERVER – Weekly Series – Memory Lane – #047 | Journey to SQL Authority with Pinal Dave

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