Basic SQL Interview Questions for Freshers with Answers
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If you’re a fresher looking to kickstart your career in the field of data management, then it’s essential to have a strong foundation in SQL. SQL, or Structured Query Language, is a programming language used to manage relational databases. As an aspiring data analyst or database developer, you’ll likely encounter SQL interview questions during your job search. Consider enrolling in Web Development training to acquire the necessary skills and knowledge in SQL and other in-demand technologies.
To help you prepare, we’ve compiled a list of some of the most common basic SQL interview questions for freshers.
- What is SQL, and what are its uses?
SQL stands for Structured Query Language and is a programming language used for managing relational databases. SQL is used to create and modify databases, retrieve data from databases, and perform various database management tasks.
- What is a database?
A database is a structured collection of data that is stored and organized in a way that allows easy access and retrieval of information.
- What is a table?
A table is a collection of data organized in rows and columns. It consists of columns, which represent the attributes or characteristics of the data, and rows, which represent individual records or instances of the data.
- What is a primary key?
A primary key is a unique identifier for each record in a table. It is a column or set of columns that uniquely identify each row in the table.
- What is a foreign key?
A foreign key is a column or set of columns in a table that refer to the primary key of another table. It is used to establish a relationship between two tables.
- What is a view?
A view is a virtual table that is created based on the result of a SELECT statement. It is used to simplify complex queries and provide a more intuitive representation of the data.
- What is normalization?
Normalization is the process of organizing data in a database to reduce redundancy and dependency. It involves breaking down large tables into smaller tables and establishing relationships between them.
- What is a stored procedure?
A stored procedure is a set of SQL statements that are stored in the database and can be executed as a single unit. It is used to simplify complex operations and improve performance.
- What is a trigger?
A trigger is a set of SQL statements that are automatically executed in response to a specific event or action, such as an insert, update, or delete operation.
- What is a join?
A join is an operation that combines rows from two or more tables based on a related column between them.
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- What is a subquery?
A subquery is a query that is embedded within another query. It is used to retrieve data that will be used in the main query.
- What is a union?
A union is an operation that combines the results of two or more SELECT statements into a single result set.
- What is a transaction?
A transaction is a set of SQL statements that are executed as a single unit. It is used to ensure data integrity and consistency.
- What is indexing?
Indexing is the process of creating an index for a table to improve the speed of data retrieval. It involves creating a data structure that allows for faster searching and sorting of data.
- What is a cursor?
A cursor is a database object used to manipulate data row by row. It is used to process data in a loop and perform various operations on each row.
- What is a deadlock?
A deadlock is a situation where two or more transactions are waiting for each other to release a resource, such as a database lock. It can result in a deadlock and cause the transactions to fail.
- What is a clustered index?
A clustered index is an index that determines the physical order of data in a table. It is created on the primary key column of a table.
- What is a non-clustered index?
A non-clustered index is an index that does not determine the physical order of data in a table. It is created on a non-primary key column of a table.
- What’s the distinction between DBMS and RDBMS?
A database management system (DBMS) is a software system that manages databases and may or may not enforce data linkages, normalization, and consistency.
RDBMS, on the other hand, is a form of DBMS that enforces data associations through the use of keys and assures data consistency through the use of ACID characteristics. RDBMS is better suited for huge and complicated datasets, and data must be normalized for greater efficiency.
- What is the function of the SQL GROUP BY clause?
The SQL combines BY clause is used to combine rows with the same values in one or more columns into summary rows, which are then used to compute sums, averages, counts, and other aggregate functions over those groups.
The GROUP BY clause’s aim is to organize data into groups that may be evaluated in the aggregate, such as total sales by region, average wage by department, or client orders.
In conclusion, this article has provided comprehensive answers to common SQL interview questions. Whether you are a beginner or an experienced professional, mastering SQL is essential for success in the ever-expanding data-driven industry. If you’re seeking Industrial Training in Chandigarh to enhance your SQL skills and gain practical experience, consider exploring the numerous opportunities available in this vibrant city. By harnessing the power of SQL, you can unlock the potential of data analysis and contribute to the growth and innovation of various industries.
