Top 100 SQL Interview Questions – Testprep Training Blog

Top 100 SQL Interview Questions – Testprep Training Blog

Nearly all SQL job applicants go through the same nerve-wracking process. It is difficult to know if you have enough SQL knowledge to pass the exam and, more importantly, to prepare for the questions that will be asked during the interview. There are many types of SQL database jobs available to companies looking for new skills. We have everything you need to help you prepare for your interview.
SQL programming skills are highly sought-after and in demand in the market. Database Management Systems (DBMS), which are used in almost every software application, is a huge value. Interviews are a crucial part of securing a job. They will be asked several SQL questions. We have compiled a list with answers to common SQL interview questions that are likely to be asked during the interview. Candidates may be asked basic to advanced level SQL questions depending on their knowledge and other factors.
1. What do you know about Database?
A database is a collection of data that can be stored and recovered digitally from remote or local computers. Databases can also be complex and large. These databases are created using modeling and fixed design procedures.
2. What is DBMS?
A (DBMS), Database Management System, is a plan that manages the creation, maintenance, and performance of a database. DBMS can also be called File Manager, which manages data in a database and not in file systems.
3. What is SQL?
Structured Query Language, or SQL, is used to interact with the Database. This is a standard language that can be used to perform tasks such as updating, retrieval, deletion and insertion of data from a Database.
4. Define Data Warehouse
A data warehouse is a central repository for data from different sources. These data are combined, modified and made available for online processing as well as mining.
5. What is a table in a Database?
A table is a database object that is used to save records in a field with rows and columns.
6. What are the different subsets of SQL?
Data Definition Language (DDL), – This allows you to execute various operations on your database, such as ALTER, CREATE, or DELETE objects.
Data Manipulation Language, (DML) – This allows you to access and manipulate data. It also allows you to insert, delete, update, and recover data from a database.
Data Control Language (DCL), it allows you to control access to the database. You can grant, revoke access permissions.
7. What is the difference between SQL & MySQL?
SQL is a standard language for creating and recovering structured databases. MySQL, on the other hand, is a relational database management operation like Oracle, SQL Server or IBM DB2, which is used to maintain SQL databases.
8. What are the differences between DBMS and DBMS?
There are two types of DBMS:
Relational Database Management System: The data are collected in relations (tables). MySQL is an example.
Non-Relational Database Management Systems: There are no theories, tuples, or attributes. MongoDB is an example.
9. What are tables and fields?
A table is a collection data that is organized in a model with Rows or Columns. The columns can be classified as horizontal or vertical. On the other hand, rows can be classified in both vertical and horizontal categories. A table can have a set number of columns called fields, but it can also have any number or records.
10. What does join in SQL mean?
A JOIN clause allows you to combine rows from multiple tables based on a related row.
11. What are the different types of joins?
There are four types:
Inner join:Inner join in SQLis the most common type of join. It is used to return all rows from tables where the join condition has been met.