Interview Questions And Answers Pdf

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Basic & Advanced SQL Interview Questions And Answers:

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Interview Questions And Answers Pdf Free Download

Interview – Sample Questions and Answers (April 2017) Tell me about yourself This is usually one of the first questions asked at interview because it is a good ice-breaker. You should always have a finely tuned response prepared in advance. Structure your answer around the job. Mar 04, 2018 hvac interview questions and answers pdf, hvac interview questions for freshers, hvac technician interview questions and answers pdf, common hvac interview questions, hvac technician interview questions and answers, hvac technical interview questions, hvac draftsman interview questions. Sample Interview Questions with Suggested Ways of Answering Q. Tell me about yourself. This is the dreaded, classic, open-ended interview question and likely to be among the first.

Congratulations! You got the interview! In this SQL Server Developer Interview Questions post, we have put together both basic and advanced SQL Interview Questions and Answers. This post contains Top SQL Interview Questions for Experienced as well as Freshers.

I have segregated this “SQL Server Interview Questions” post into two types.

1. Common SQL Interview Questions
2. Practical SQL Query Interview Questions (SQL Server Queries examples with answers).

I don’t want to take much time of yours but I couldn’t move further without mentioning about this inevitable job interview question which every hiring manager asks you in any interview i.e., Tell Me About Yourself. Answering these questions is very easy if you follow the link. It contains sample answers for both freshers and experienced. Now, Let’s move on to the actual post.

General SQL Interview Questions:

1. What is a Database?
A database is a collection of information in an organized form for faster and better access, storage and manipulation. It can also be defined as a collection of tables, schema, views, and other database objects.

2. What is Data warehouse?
Data warehouse refers to a central repository of data from multiple sources of information. Those data are consolidated, transformed and made available for the mining as well as online processing.

3. What is a Table in a Database?
A table is a database object used to store records in a field in the form of columns and rows that holds data.

4. What is a Field in a Database?
A field in a Database table is a space allocated to store a particular record within a table.

5. What is a Record in a Database?
A record (also called a row of data) is an ordered set of related data in a table.

6. What is a column in a Table?
A column is a vertical entity in a table that contains all information associated with a specific field in a table.

7. What is DBMS?
Database Management System is a collection of programs that enables a user to store, retrieve, update and delete information from a database.

8. What are the types of DBMS?
There are two types of DBMS
1. Relational Database Management System (RDBMS)
2. Non-Relational Database Management System

9. What is RDBMS?
RDBMS stands for Relational Database Management System. RDBMS is a database management system (DBMS) that is based on the relational model. Data from a relational database can be accessed using Structured Query Language (SQL)

10. What are the popular Database Management Systems in the IT Industry?
Oracle, MySQL, Microsoft SQL Server, PostgreSQL, Sybase, MongoDB, DB2, and Microsoft Access etc.,

11. What is SQL?
SQL Overview: SQL stands for Structured Query Language. It is an American National Standard Institute (ANSI) standard. It is a standard language for accessing and manipulating databases. Using SQL, some of the action we could do are to create databases, tables, stored procedures (SP’s), execute queries, retrieve, insert, update, delete data against a database.

12. What are the different types of SQL commands?
SQL commands are segregated into the following types:

DDL – Data Definition Language
DML – Data Manipulation Language
DQL – Data Query Language
DCL – Data Control Language
TCL – Transaction Control Language

13. What are the different DDL commands in SQL?
DDL commands are used to define or alter the structure of the database.

CREATE: To create databases and database objects
ALTER: To alter existing database objects
DROP: To drop databases and databases objects
TRUNCATE: To remove all records from a table but not its database structure
RENAME: To rename database objects

14. What are the different DML commands in SQL?
DML commands are used for managing data present in the database.

SELECT: To select specific data from a database
INSERT: To insert new records into a table
UPDATE: To update existing records
DELETE: To delete existing records from a table

15. What are the different DCL commands in SQL?
DCL commands are used to create roles, grant permission and control access to the database objects.

GRANT: To provide user access
DENY: To deny permissions to users
REVOKE: To remove user access

16. What are the different TCL commands in SQL?
TCL commands are used to manage the changes made by DML statements.

COMMIT: To write and store the changes to the database
ROLLBACK: To restore the database since the last commit

17. What is an Index?
An index is used to speed up the performance of queries. It makes faster retrieval of data from the table. The index can be created on one column or a group of columns.

18. What are all the different types of indexes?
There are three types of indexes
1. Unique Index: Unique Indexes helps maintain data integrity by ensuring that no two rows of data in a table have identical key values. A unique index can be applied automatically when a primary key is defined. It ensures that the values in the index key columns are unique.
2. Clustered Index: Clustered Index reorders the physical order of the table and search based on the key values. There will be only one clustered index per table.
3. Non-Clustered Index: Non-Clustered Index doesn’t alter the physical order of the table and maintains a logical order of the data. Each table can have many non-clustered indexes.

19. What is the difference between Cluster and Non-Cluster Index?
The difference between the clustered and non-clustered index in SQL is as follows:
Clustered Index:
It is used for easy retrieval of data from the database and it is faster.
One table can only have one clustered index
It alters the way records are stored in a database as it sorts out rows by the column which is set to be clustered index.
Non-Clustered Index:
It is slower compared to the Clustered index.
One table can have multiple non clustered index
It doesn’t alter the way it was sorted but it creates a separate object within a table which points back to the original table rows after searching.

20. What is a View?
A view is like a subset of a table which is stored logically in a database. A view is a virtual table. It contains rows and columns similar to a real table. The fields in the view are fields from one or more real tables. Views do not contain data of their own. They are used to restrict access to the database or to hide data complexity.

Gravostyle 8 manual. Developed by engravers for engravers, this management software for mechanical and laser engraving machines is a benchmark in the industry.<p><p><strong>52. What are all the different Normalization? </strong><br>There are different types of Normalization forms in SQL.</p><ul><li>First Normal Form (1NF)</li><li>Second Normal Form (2NF)</li><li>Third Normal Form (3NF)</li><li>Boyce and Codd Normal Form (BCNF)</li></ul><p><strong>53. What is Denormalization?</strong><br>Denormalization is a database optimization technique used to increase the performance of a database infrastructure. It involves in the process of adding redundant data to one or more tables. In a normalized database, we store data in separate logical tables and attempt to minimize redundant data.</p><p><strong>54. What is Stored procedure?<br></strong>A Stored Procedure is a collection of SQL statements that have been created and stored in the database to perform a particular task. The stored procedure accepts input parameters and processes them and returns a single value such as a number or text value or a result set (set of rows).</p><p><strong>55. What is a Trigger?</strong><br>A Trigger is a SQL procedure that initiates an action in response to an event (Insert, Delete or Update) occurs. When a new Employee is added to an Employee_Details table, new records will be created in the relevant tables such as Employee_Payroll, Employee_Time_Sheet etc.,</p><p><strong>56. Explain SQL Data Types?<br></strong>In SQL Server, each column in a database table has a name and a data type. We need to decide what type of data to store inside each and every column of a table while creating a SQL table.</p><p><strong>57. What are the possible values that can be stored in a <em>BOOLEAN</em> data field?</strong><br><em>TRUE</em> and <em>FALSE</em></p><p><strong>58. What is the largest value that can be stored in a <em>BYTE</em> data field?<br></strong>The largest number that can be represented in a single byte is 11111111 or 255. The number of possible values is 256 (i.e. 255 (the largest possible value) plus 1 (zero), or 2<strong><sup>8</sup>).</strong></p><p><strong>59. What are Operators available in SQL?</strong><br>SQL Operator is a reserved word used primarily in an SQL statement’s WHERE clause to perform operations, such as arithmetic operations and comparisons. These are used to specify conditions in an SQL statement.</p><p>There are three types of Operators.</p><ol><li>Arithmetic Operators</li><li>Comparison Operators</li><li>Logical Operators</li></ol><p><strong>60. Which TCP/IP port does SQL Server run?</strong><br>By default, it is 1433</p><p><strong>61. List out the ACID properties and explain? </strong><br>Following are the four properties of ACID. These guarantees that the database transactions are processed reliably.</p><img src=' http://www.resultuniraj.co.in/wp-content/uploads/2016/12/best-bank-interview-questions-and-answers-1024x883.png' =""="" alt='Interview questions and answers pdf file' title='Interview questions and answers pdf file'>

Atomicity
Consistency
Isolation
Durability

62. Define the SELECT INTO statement.
The SELECT INTO statement copies data from one table into a new table. The new table will be created with the column-names and types as defined in the old table. You can create new column names using the AS clause.

Interview Questions And Answers Pdf Download<table><tbody><tr><td><div><span>SELECT *</span><span>INTO </span><span>newtable </span><span>FROM </span><span>oldtable </span><span>WHERE </span><span>condition</span><span>;</span></div></td></tr></tbody></table><p><strong>63. What is the difference between Delete, Truncate and Drop command?</strong><br>The difference between the Delete, Truncate and Drop command is</p><ul><li>Delete command is a DML command, it is used to delete rows from a table. It can be rolled back.</li><li>Truncate is a DDL command, it is used to delete all the rows from the table and free the space containing the table. It cant be rolled back.</li><li>Drop is a DDL command, it removes the complete data along with the table structure(unlike truncate command that removes only the rows). All the tables’ rows, indexes, and privileges will also be removed.</li></ul><p><strong>64. What is the difference between Delete and Truncate?</strong><br>The difference between the Delete, and Truncate are</p><table><thead><tr><th>DELETE</th><th>TRUNCATE</th></tr></thead><tbody><tr><td>Delete statement is used to delete rows from a table. It can be rolled back.</td><td>Truncate statement is used to delete all the rows from the table and free the space containing the table. It cant be rolled back.</td></tr><tr><td>We can use WHERE condition in DELETE statement and can delete required rows</td><td>We cant use WHERE condition in TRUNCATE statement. So we cant delete required rows alone</td></tr><tr><td>We can delete specific rows using DELETE</td><td>We can only delete all the rows at a time using TRUNCATE</td></tr><tr><td>Delete is a DML command</td><td>Truncate is a DDL command</td></tr><tr><td>Delete maintains log and performance is slower than Truncate</td><td>Truncate maintains minimal log and performance wise faster</td></tr><tr><td>We need DELETE permission on Table to use DELETE command</td><td>We need at least ALTER permission on the table to use TRUNCATE command</td></tr></tbody></table><p><strong>65. What is the difference between Union and Union All command?</strong><br>This is one of the tricky SQL Interview Questions. Interviewer may ask you this question in another way as what are the advantages of Union All over Union.</p><p>Both Union and Union All concatenate the result of two tables but the way these two queries handle duplicates are different.</p><p><strong><em>Union: </em></strong>It omits duplicate records and returns only distinct result set of two or more select statements.<br><strong><em>Union All:</em></strong> It returns all the rows including duplicates in the result set of different select statements.</p><p>Performance wise Union All is faster than Union, Since Union All doesn’t remove duplicates. Union query checks the duplicate values which consumes some time to remove the duplicate records.</p><p>Assume: <em>Table1</em> has 10 records, <em>Table2</em> has 10 records. Last record from both the tables are same.</p><p>If you run Union query.</p><table><tbody><tr><td><div>2</div></td><td><div><span>UNION</span></div></td></tr></tbody></table><p><strong>Output:</strong> Total 19 records</p><p>If you run Union query.</p><table><tbody><tr><td><div>2</div></td><td><div><span>UNION </span><span>ALL</span></div></td></tr></tbody></table><p><strong>Output:</strong> Total 20 records</p><p><em>Data type of all the columns in the two tables should be same.</em></p><p><strong>66. What is CLAUSE in SQL?<br></strong>SQL CLAUSE helps to limit the result set by providing a condition to an SQL Query. A CLAUSE helps to filter the rows from the entire set of records. SQL CLAUSES are WHERE & HAVING.</p><p><strong>67. What is the difference between Having and Where clause?<br></strong>Where clause is used to fetch data from a database that specifies particular criteria whereas a Having clause is used along with ‘GROUP BY’ to fetch data that meets particular criteria specified by the Aggregate functions. Where clause cannot be used with Aggregate functions, but the Having clause can.</p><p><strong>68. What are aggregate functions in SQL?<br></strong>SQL aggregate functions return a single value, calculated from values in a column. Some of the aggregate functions in SQL are as follows</p><ul><li>AVG() – This function returns the average value</li><li>COUNT() – This function returns the number of rows</li><li>MAX() – This function returns the largest value</li><li>MIN() – This function returns the smallest value</li><li>ROUND() – This function rounds a numeric field to the number of decimals specified</li><li>SUM() – This function returns the sum</li></ul><p><strong>69. What are string functions in SQL?</strong><br>SQL string functions are used primarily for string manipulation. Some of the widely used SQL string functions are</p><ul><li>LEN() – It returns the length of the value in a text field</li><li>LOWER() – It converts character data to lower case</li><li>UPPER() – It converts character data to upper case</li><li>SUBSTRING() – It extracts characters from a text field</li><li>LTRIM() – It is to remove all whitespace from the beginning of the string</li><li>RTRIM() – It is to remove all whitespace at the end of the string</li><li>CONCAT() – Concatenate function combines multiple character strings together</li><li>REPLACE() – To update the content of a string.</li></ul><p><strong>70. What are user defined functions?</strong><br>As the name suggests these are written by users as per their requirement. User-defined functions are the functions written to use a logic whenever required.</p><p><strong>71. What are all types of user-defined functions?</strong><br>There are three types of user-defined function, namely<br>• Scalar Functions<br>• Inline Table-valued functions<br>• Multi-statement valued functions</p><p>Scalar functions return unit, variant defined the return clause.<br>Inline Table-valued functions and Multi-statement valued functions return table as a return.</p><p><strong>72. What is Self-Join?</strong><br>A self-join is a join in which a table is joined with itself, especially when the table has a Foreign Key which references its own Primary Key.</p><p><strong>73. What is Cross-Join?</strong><br>Cross join produces a result set which is the number of rows in the first table multiplied by a number of rows in the second table if no WHERE clause is used along with Cross join. This kind of result is known as Cartesian Product. If suppose, Where clause is used in cross join then the query will work like an Inner join.</p><p><strong>74. What is Collation?</strong><br>Collation is defined as a set of rules that determine how character data can be sorted as well as compared. Character data is sorted using rules that define the correct character sequence along with options for specifying case-sensitivity, character width, accent marks, kana character types.</p><p><strong>75. What are all different types of collation sensitivity?</strong><br>Different types of collation sensitivity are as follows<br>Case Sensitivity: A and a and B and b.<br>Kana Sensitivity: Japanese Kana characters.<br>Width Sensitivity: Single byte character and double byte character.<br>Accent Sensitivity.</p><h3><strong>Practical SQL Interview Questions:</strong></h3><p>In this part, we will see SQL practice questions which contain both complex SQL queries interview questions and basic SQL Interview Questions. Let’s see important SQL queries for interview</p><p><strong>76. How to get unique records from a table?</strong><br>By using DISTINCT keyword, we can get unique records from a table</p><p><strong>77. What is the command used to fetch the first 5 characters of a string?</strong><br>Some of the ways to fetch the first 5 characters of a string are as follows:</p><div><textarea wrap='soft' readonly='>SELECT RIGHT(EmpName,5) AS EmployeeName FROM EmployeeSELECT SUBSTRING(EmpName,1,5) AS EmployeeName FROM Employee

2	SELECT RIGHT(EmpName,5)ASEmployeeName FROM Employee SELECT SUBSTRING(EmpName,1,5)ASEmployeeName FROM Employee

78. How to add new Employee details in an Employee_Details table with the following details
Employee_Name: John, Salary: 5500, Age: 29?

Top Interview Questions 2019<p><strong>79. How to add a column ‘Salary’ to a table Employee_Details?</strong></p><p><strong>80. How to change a value of the field ‘Salary’ as 7500 for an Employee_Name ‘John’ in a table Employee_Details?</strong></p><div><textarea wrap='soft' readonly='>UPDATE Employee_Details set Salary = 7500 where Employee_Name = ‘John’;

UPDATE Employee_Details set Salary=7500where Employee_Name=‘John’;

81. Write an SQL Query to select all records from the table?

82. How To Get List of All Tables From A DataBase?
To view the tables available on a particular DataBase

83. Define SQL Delete statement.
The SQL Delete statement is used to delete records from a table.

SELECT *FROM Employee_Details WHERE Employee_Name like'E%';

Output:

2	sp_rename'TableName.OldColumnName','NewColumnName'

94. How to select all the even number records from a table?
To select all the even number records from a table:

95. How to select all the odd number records from a table?
To select all the odd number records from a table:

96. What is the SQL CASE statement?
SQL Case statement allows embedding an if-else like clause in the SELECT statement.

97. Can you display the result from the below table TestTable based on the criteria M,m as M and F, f as F and Null as N and g, k, I as U

50 Interview Questions And Answers

case

when Gender='g'then'U'

when Gender='NULL'then'N'

endasnewgender from TestTable GROUP BY Gender

98. What will be the result of the query below?

select casewhen null=nullthen'True'else'False'endasResult;

This query returns “False”. In the above question, we could see null = null is not the proper way to compare a null value. To compare a value with null, we use IS operator in SQL.

So the correct way is as follows

Interview Questions And Answers Pdf Free Download

select casewhen nullisnullthen'True'else'False'endasResult;

99. What will be the result of the query below?

select casewhen nullisnullthen'Queries In SQL Server'else'Queries In MySQL'endasResult;

This query will returns “Queries In SQL Server”.

100. How do you update F as M and M as F from the below table TestTable?

UPDATE TestTable SET Gender=CASEGender WHEN'F'THEN'M'ELSE'F'END

101. Describe SQL comments?
Single Line Comments: Single line comments start with two consecutive hyphens (–) and ended by the end of the line
Multi-Line Comments: Multi-line comments start with /* and end with */. Any text between /* and */ will be ignored.

102. What is the difference between NVL function, IFNULL function, and ISNULL function?
These three functions work in the same way. These functions are used to replace NULL value with another value. Oracle developers use NVL function, MySQL developers use IFNULL function and SQL Server developers use ISNULL function.
Assume, some of the values in a column are NULL.
If you run below statement, you will get result as NULL

Suppose any of the value in col3 is NULL then as I said your result will be NULL.

To overcome this we use NVL() function, IFNULL() function, ISNULL() Function. Call of duty play online no download.

ORACLE:

MySQL:

Also, you can use the COALESCE() function

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Interview Questions And Answers Pdf

Basic & Advanced SQL Interview Questions And Answers:

General SQL Interview Questions:

50 Interview Questions And Answers

Interview Questions And Answers Pdf Free Download

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