sql Interview Questions and Answers in 2025 (100+ Q&A)

Ques:- Explain open SQL vs native SQL?

Asked In :- Milliman India, CodeCraft Technologies, Attra Infotech, ETEA, Redisolve, Tessolve, HARITA TECHSERV, IT Cube Solutions, Test Yantra, Acrotrend Solutions,

Right Answer:
Open SQL is a database-independent SQL interface provided by SAP that allows developers to write queries without worrying about the underlying database system. It translates the queries into the appropriate SQL dialect for the specific database being used.

Native SQL, on the other hand, refers to the SQL syntax specific to a particular database management system (DBMS). It allows for the use of advanced features and optimizations specific to that DBMS but is not portable across different systems.

Database Architect/ Designer SQL Server

Ques:- When do you get constraint violation? What are the types of constraints?

Asked In :- Sify Technologies, New Vision Info Tech, Rudder Analytics, ConQsys Information Technology, i-exceed technology solutions, StockEdge, Thorogood, VassarLabs, Saffron Global Corp, Perennial System,

Right Answer:
A constraint violation occurs when an operation violates the rules defined by a constraint in the database, such as trying to insert a duplicate value in a column that requires unique values. The types of constraints include:

1. **Primary Key Constraint** - Ensures that each row has a unique identifier.
2. **Foreign Key Constraint** - Ensures referential integrity between tables.
3. **Unique Constraint** - Ensures all values in a column are unique.
4. **Check Constraint** - Ensures that all values in a column meet a specific condition.
5. **Not Null Constraint** - Ensures that a column cannot have a NULL value.

Database Architect/ Designer SQL Server

Ques:- Difference between “ORACLE” and “MICROSOFT ACCESS” databases.

Asked In :- Celestial Systems Pvt., TripStack (ALP Consulting), Winshuttle Software (India), FIN Infocom, Next Wave, SpringRole, bluCursor Technologies, UTS Consultants, NAVYA, MiGrocer,

Right Answer:
Oracle is a powerful, enterprise-level relational database management system (RDBMS) designed for large-scale applications with high performance and scalability, while Microsoft Access is a desktop database application suitable for small to medium-sized applications, offering a user-friendly interface but limited scalability and performance compared to Oracle.

Project Leader/ Project Manager SQL Server

Ques:- Can we generate a trigger for two tables? if so what is the query to generate a trigger for two tables employee table and department table with employee having department no.

Asked In :- CBRE South Asia, Techwave Consulting Inc, SSA, Streebo Solutions, DCM Shriram, Iprimed Education Solutions, Advantage Club, MindBowser Info Solutions, Vontobel, HiLabs,

Right Answer:
No, you cannot create a single trigger that directly responds to events on two different tables in SQL Server. You need to create separate triggers for each table. Here’s an example of how to create triggers for both the `employee` and `department` tables:

For the `employee` table:
```sql
CREATE TRIGGER trg_employee
ON employee
AFTER INSERT, UPDATE
AS
BEGIN
-- Trigger logic for employee table
END
```

For the `department` table:
```sql
CREATE TRIGGER trg_department
ON department
AFTER INSERT, UPDATE
AS
BEGIN
-- Trigger logic for department table
END
```

Data Warehouse Developer SQL Server

Ques:- I was asked in an interview…”Suppose u have a field with UNIQUE KEY. can u leave two or more cells NULL in SQL Server 2005…If Yes then Why…if NOT then Why…..

Asked In :- Atul, ProtoTech Solutions, ACC Cement, Karza Technologies, Statista, Javelin, Cue Health Inc, ficosa, intrasoft international, infrasoft technologies,

Right Answer:
Yes, you can leave two or more cells NULL in a field with a UNIQUE KEY in SQL Server 2005. This is because NULL values are considered distinct from each other, allowing multiple NULLs in a column with a UNIQUE constraint.

Database Architect/ Designer SQL Server

Ques:- What is the use of Analyzing the tables?

Asked In :- Xoriant Solutions Pvt Ltd, SenecaGlobal IT Services, Coviam Technologies, C E I India, eGain Communications, Unistring Tech Solutions, Triad Software, WSP, Freight Tiger, Trak Global,

Right Answer:
Analyzing tables helps optimize query performance by updating statistics about the data distribution, which the SQL Server query optimizer uses to create efficient execution plans.

Database Architect/ Designer SQL Server

Ques:- Give some examples of Analytical functions.

Asked In :- InfoObjects, Cloud Assert, Shriram Finance, O P Jindal Global University, Quadrant Resource, Cloud Analogy, Agaram InfoTech, The Calculus, Aggregate Intelligence, Influx Solution,

Right Answer:
Examples of analytical functions in SQL Server include:

1. ROW_NUMBER()
2. RANK()
3. DENSE_RANK()
4. NTILE()
5. SUM() OVER()
6. AVG() OVER()
7. COUNT() OVER()

Database Architect/ Designer SQL Server

Ques:- How to create a database link?

Asked In :- Grid Logic Software, POPCORNAPPS SOFTWARE PVT, Citrus Informatics (India), ProV Infotech Systems, Diya Systems (Mangalore), Dhyan Infotech, Hestabit Technologies, DataMetica, redBus India, Capital Numbers,

Right Answer:
To create a database link in SQL Server, you can use a linked server. Here’s the SQL command:

```sql
EXEC sp_addlinkedserver
@server='LinkedServerName',
@srvproduct='',
@provider='SQLNCLI',
@datasrc='RemoteServerName';
```

Replace `LinkedServerName` with your desired name for the link and `RemoteServerName` with the name of the remote server you want to connect to.

Database Architect/ Designer SQL Server

Ques:- Difference – Primary Key and Aggregate Key

Asked In :- Netaxis IT Solutions (p), FUTURISM TECHNOLOGIES PVT, Triassic Solutions, First Zen, Invimatic, Eternus Solutions, Twilio, Searce, Sweans Technologies, Savantis,

Right Answer:
A Primary Key is a unique identifier for a record in a table, ensuring that no two rows have the same value in that column. An Aggregate Key, on the other hand, is a combination of two or more columns used together to uniquely identify a record, often used in scenarios where a single column is not sufficient to ensure uniqueness.

Data Warehouse Developer SQL Server

Ques:- Which of the following modules within SQL Server 2005 cannot be signed with a digital signature?

Asked In :- Addweb solutions, Helical It Solutions, Innominds Software (P), Estuate, G S Lab, PEOL, Miracle Software Systems, Searce, DCM Shriram, Tower Research Capital LLC,

Right Answer:
The SQL Server 2005 modules that cannot be signed with a digital signature are the system stored procedures.

Project Leader/ Project Manager SQL Server

Ques:- What are data objects?

Asked In :- MBR Informatics, Damco Solutions, Verticurl Marketing, Gem Software Solutions, ETEA, Junior Assistant, PRAN-RFL, Agicent Technologies, tringapps, Kloudrac,

Right Answer:
Data objects are instances of data structures that represent and encapsulate data in a specific format, allowing for organized storage, retrieval, and manipulation of that data within a database or application.

Data Warehouse Developer SQL Server

Ques:- Where does Profiler store its temporary data in SQL Server 2005?

Asked In :- FUTURISM TECHNOLOGIES PVT, New Vision Info Tech, Posist Technologies, Utthunga, Analyttica Datalab, Doshi Accounting and Services, Amberjack, TP1, Melio Systems, dataeaze systems,

Right Answer:
Profiler stores its temporary data in the tempdb database in SQL Server 2005.

Database Architect/ Designer SQL Server

Ques:- What is Extended Stored Procedure in SQL Server 2000?

Asked In :- sciative, Pi Techniques, MaxVal-IP Services, Ginni Systems, Innofied Solution, Simeio, Glenwood Systems, Mechlin Technologies, Onebill software, Carisma Solutions,

Right Answer:
An Extended Stored Procedure in SQL Server 2000 is a special type of stored procedure that allows you to execute external programs or functions written in languages like C or C++. It enables SQL Server to interact with the operating system and perform tasks that are not possible with standard T-SQL.

Data Warehouse Developer SQL Server

Ques:- What does this return? select (1324 & 1024)

Asked In :- Netaxis IT Solutions (p), Itobuz Technologies, InfoObjects, Riversand Global Technologies, Bristlecone India, Renault Nissan, SPCL, Streebo Solutions, iProgrammer, iauro systems,

Right Answer:
The query returns 1024.

Project Leader/ Project Manager SQL Server

Ques:- What is the difference between Inner join and full outer join in terms of the Number of rows return

Asked In :- Razorpay-Startup, Sify Technologies, Aruba Networks, Promantia Consulting LLP, ConvergeSol, NAB - National Australia Bank, Spericorn, FinEdge, Embibe, CoreCompete,

Right Answer:
An Inner Join returns only the rows that have matching values in both tables, while a Full Outer Join returns all rows from both tables, with matching rows from both sides where available, and NULLs where there are no matches.

Database Architect/ Designer SQL Server

Ques:- How to get the list of tables in Sybase?

Asked In :- Priya Softweb Solutions, Cloud Kinetics Technology Solutions, Sify Technologies, Travanleo Info Solutions India, Zentron Labs, Xoriant Solutions, Aurus Tech, TPF Technologies, ScriptsHub Technologies, chetu,

Right Answer:
To get the list of tables in Sybase, you can use the following SQL query:

```sql
SELECT name FROM sysobjects WHERE type = 'U';
```

Data Warehouse Developer SQL Server

Ques:- What is the difference between Inner join and full outer join in terms of the Number of rows returned?

Asked In :- Cybernext, OIP, Blueshift India, OfBusiness, Savantis, Kloudrac, XorLabs, Datagrokr, Adloid, Fastlab,

Right Answer:
An Inner Join returns only the rows that have matching values in both tables, while a Full Outer Join returns all rows from both tables, with matching rows where available, and NULLs where there are no matches. Therefore, the number of rows returned by a Full Outer Join can be greater than or equal to that of an Inner Join.

Project Leader/ Project Manager SQL Server

Ques:- Explain about Dead-locks in Sql Server database

Asked In :- Hidden Brains InfoTech, Systematix Infotech, Zenon, CareerNet, PRAN-RFL, Quality Kiosk, Invenger Technologies, TekLink International, AWC Software, HummingWave Technologies,

Right Answer:
A deadlock in SQL Server occurs when two or more transactions are waiting for each other to release locks on resources, creating a cycle of dependencies that prevents any of the transactions from proceeding. SQL Server automatically detects deadlocks and resolves them by terminating one of the transactions, allowing the other to continue.

Data Warehouse Developer SQL Server

Ques:- What does the Queue Reader Agent do in SQL Server 2005 replication?

Asked In :- LiteBreeze Infotech, Principal Global Services, NSOFT SOLUTIONS, Hexaview Technologies private, Fulcrum Logic (I), Aris Global Software, Goldstone Technologies, District Cooperative Central Bank DCCB, ATMECS, Shiash Info Solutions,

Right Answer:
The Queue Reader Agent in SQL Server 2005 replication is responsible for reading messages from the distribution queue and applying them to the subscriber databases in a transactional replication setup.

Data Warehouse Developer SQL Server

Ques:- In which order do you perform an upgrade to SQL Server 2005 for replicated databases?

Asked In :- CBRE South Asia, Aurus Tech, SRS Business Solutions (India), Terralogic, IDeaS - A SAS Company, DCM Shriram, Heptagon Technologies, Saffron Global Corp, Infometry, FlyNava Technologies,

Right Answer:
1. Remove replication from the databases.
2. Upgrade the SQL Server instance to SQL Server 2005.
3. Reconfigure replication for the databases.

SQL, or Structured Query Language, is the essential tool for anyone working with relational databases. It serves as the universal language for interacting with these databases, allowing users to organize, retrieve, and manage vast amounts of data effectively. Developed in the 1970s, SQL has become the standardized method for database communication across a wide range of applications, from small business systems to enterprise-level data warehouses.

The power of SQL lies in its declarative nature. Instead of telling the computer how to find data, you simply tell it what data you want. This is done through a concise set of commands, such as SELECT to retrieve data, INSERT to add new records, UPDATE to modify existing records, and DELETE to remove them. These commands, often combined with clauses like WHERE to filter data and JOIN to link tables, enable complex data operations with relatively simple statements. For example, a single query can retrieve a list of all customers from a specific city, calculate their total spending, and sort the results by name.

SQL is a foundational technology for data science, business intelligence, and web development. It is used to query databases that power everything from social media platforms to banking systems. Its reliability, efficiency, and widespread adoption make it an indispensable skill for database administrators, developers, and data analysts. Mastering SQL provides the ability to unlock insights from data, maintain data integrity, and build robust, data-driven applications.

Questions in: sql

What makes Takluu valuable for interview preparation?

Get Our Mobile App

Programming

Reasoning

Network & Telecom

Management

What makes Takluu valuable for interview preparation?