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Mar 27, 2024 · This article provided a curated selection of SQL query interview questions covering essential concepts such as SELECT statements, filtering data with WHERE clauses, sorting results with ORDER BY, joining tables, and utilizing aggregate functions.
Jan 8, 2024 · SQL Interview Questions – SQL Queries. Author: Lukas Vileikis. Length: 6 MINS. Type: GUIDE. Published: 2024-01-08. intro. SQL query-related SQL interview questions are some of the most frequent interview questions for junior and senior engineers alike. Preface. Database management systems are built on the premise of queries.
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What are SQL query interview questions?
What should you do in a SQL interview?
What questions should I ask in a SQL exam?
What is a SQL query?
- General SQL Questions and Answers
- Basic SQL Technical Interview Questions
- Advanced SQL Interview Questions
- SQL Interview Questions For Developers
- SQL Interview Questions For Data Analysts
- SQL Server Interview Questions
- SQL Interview FAQs
Introduce yourself.
Tech recruitersoften begin by asking candidates to introduce themselves. The purpose of this question is to ease into the interview, and to understand your interest in working for their company. Start by talking about your current role to contextualize your most recent. Then, give a brief account of your past experience and educational qualifications. Mention any SQL work you’ve done before, and any relevant classes or bootcampsthat you’ve taken. Don’t want to get too long-winded with this an...
What do you know about SQL?
Recruiters aren’t asking for an exhaustive list of every SQL topic that you’re familiar with. Rather, they’re trying to discern whether you have a general understanding of the field, and whether you have the practical experience to boot. Start with a general overview of what SQL is, and how it’s used in business contexts. Then, detail some of your learning journey, whether that’s been in college or an online course that covers SQL. Finally, tell them about your relevant projects and how you e...
Why did you opt for SQL?
Recruiters want to know why you’re passionate about SQL. Use your storytelling skills for this answer. Describe what got you interested in the field, and how you learned the relevant skills. Also explain why SQL is so important in business contexts, and how it can be used to solve important business problems.
What is SQL?
SQL stands for Structured Query Language. It is used to store, retrieve, and manipulate the data in a database.
What are the five basic SQL commands?
The five most basic SQL commands are ALTER, UPDATE, DELETE, INSERT, and CREATE.
How are SQL commands classified?
The SQL commands are classified into: 1. Data Definition Language (DDL) 2. Data Manipulation Language (DML) 3. Data Control Language (DCL) 4. Transaction Control Language (TCL) 5. Data Query Language (DQL)
What is SQL injection?
This is a code injection technique used to access unauthorized data stored in a database. An attacker exploiting an SQL injection vulnerability will often be able to view data belonging to other users in a system and in some cases even be able to modify that data. Read more about SQL injectionhere.
What is a trigger in SQL?
A trigger is a specialized procedure in SQL which runs automatically when a particular event occurs or a certain condition has been met. For example, let’s say you want to know which of the orders coming into your store need to be fulfilled within a day. In that case, you could create a trigger that looks for one-day delivery orders and transfers their information into a new table. That way you have easy access to that data in a separate table. Read more about triggersin SQL.
What is PostgreSQL?
PostgreSQL is an open-source relational database system with advanced features for enterprise use cases. It offers support for most of the popular programming languages, including Python, C, Javascript, Java, and Ruby. Read more about PostgreSQL.
How do you find duplicate records in SQL?
You can use the GROUP BY command to find the duplicate records in a row in SQL as shown below. Read more about duplicate records.
How do you delete duplicate rows in SQL?
Much like identifying duplicate rows, you can use the GROUP BY command to delete duplicate rows in SQL. To do this, delete the duplicate rows that surface when you identify the duplicates using GROUP BY. Read more about deleting rows in SQL.
What is CASE in SQL?
The CASE command is how you use if/then logic in SQL. The CASE command is followed by a WHEN statement, which corresponds to the ‘if’ in if/then logic. The WHEN clause sets a condition for the query. It then moves to the THEN part of the query, which defines what occurs if the condition is satisfied. Read more about the use of CASE statements in SQL.
Define normalization.
Normalization is the process of restructuring the data in a database so that it adheres to a certain set of rules, which are known as normal forms. This is done to improve data integrity and reduce the amount of data redundancy. Data redundancy is undesirable in a database for a few reasons, including: 1. It is tougher to maintain a database when there are many redundant records in tables. 2. Inconsistencies begin to emerge in the data. 3. Updating, inserting, and deleting anomalies becomes m...
What does it mean to denormalize a database?
Denormalization is the process of enhancing the performance of a database that has already undergone the normalization process. Read more about denormalization.
How do you identify duplicate email IDs in an SQL table?
You can use the following query to identify whether there are duplicate email IDs in an SQL table: Read more about identifying duplicate entries.
What is an SQL server?
An SQL server is a relational database management system created by Microsoft.
What is CTE in SQL Server?
CTE (common table expressions) is a temporary name given to the result of a query which you can then reference in an INSERT, DELETE, UPDATE, or SELECT statement. There are two kinds of CTEs in SQL servers. They are: Non-recursive CTEs: The subroutines in these CTEs are not repeated during processing. Recursive CTEs: These CTEs use looped procedures in their execution.
How do you change an SQL server password?
Use the following query to change the password in an SQL server: Read more about changing the password of an SQL server.
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The 80 Top SQL Interview Questions and Answers for Beginners & Intermediate Practitioners. This article provides a comprehensive overview of 80 essential SQL questions and answers for job hunters, hiring managers, and recruiters, covering both general topics and technical questions. Updated Feb 2024 · 12 min read.
SQL Query Interview Questions for freshers address fundamental SQL concepts and operations, such as selecting data from tables using SELECT statements, filtering data using WHERE clauses, manipulating data with INSERT, UPDATE, and DELETE operations, and understanding the structure of relational databases with CREATE TABLE commands.
Jan 3, 2024 · To consolidate your knowledge and concepts in DBMS, here we've listed the most commonly asked DBMS interview questions to help you ace your interview! We have classified them into the following sections: DBMS Basic Interview Questions; Intermediate DBMS Interview Questions; Advanced DBMS Interview Questions
