Top SQL Interview Questions and Answers for Freshers and Experienced Professionals

1 What is SQL

1. SQL stands for Structured Query Language and is used to store, manage and retrieve data from relational databases.

2 What is a Database

1. A database is an organized collection of data that allows easy storage, retrieval and management.

3 What is a Primary Key

1. A primary key uniquely identifies each record in a table and does not allow duplicates or null values.

4 What is a Foreign Key

1. A foreign key connects two tables and maintains relational integrity between them.

5 What is a Join

1. A join is used to combine data from two or more tables based on related columns.

6 Types of Joins

1. Inner join returns matching records
2. Left join returns all records from the left table
3. Right join returns all records from the right table
4. Full join returns both matching and non matching records

7 What is Normalization

1. Normalization is the process of organizing data to reduce redundancy and improve efficiency.

8 What is Denormalization

1. Denormalization is used to improve read performance by adding redundant data.

9 What is a Stored Procedure

1. A stored procedure is a reusable set of SQL statements stored inside the database.

10 What is an Index

1. An index improves the speed of data retrieval by working like a quick reference pointer.

11 What is a View

1. A view is a virtual table created from an SQL query that displays data dynamically.

12 Difference Between Delete and Truncate

1. Delete removes specific rows

1. Truncate removes all rows instantly and resets storage

13 What is ACID Property

1. ACID ensures reliable transactions
2. Atomicity
3. Consistency
4. Isolation
5. Durability

14 What is a Constraint

1. Constraints are rules applied to columns to maintain data accuracy and integrity.

15 Why Do Companies Test SQL Skills

1. To evaluate data handling ability
2. To check logical and analytical thinking
3. To assess real world database understanding

Conclusion

1. SQL is a must know skill for IT careers, and mastering these common interview questions boosts confidence for both freshers and experienced professionals.

1. At Revive Technologies, our SQL training programs focus on hands on practice and interview preparation to help learners become job ready.

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