Example: SQL Server. 3. What is SQL? SQL stands for Structured Query Language , and it is used to communicate with the Database. This is a standard language used to perform tasks such as retrieval, updation, insertion and deletion of data from a database. 7. What is a unique key? A...
SQL (Structured Query Language) Interview Questions And AnswersSharpen your SQL interview expertise with our handpicked 172 questions. Each question is crafted to challenge your understanding and proficiency in SQL. Suitable for all skill levels, these questions are essential for effective preparation. ...
SQL Interview Question 面试的时候发现会问一些SQL的基本问题,在此总结一下。 ProgramInterview/SQL这个网站上的问题还比较全。 1. Join type INNER JOIN: Returns all rows when there is at least one match in BOTH tables LEFT JOIN: Return all rows from the left table, and the matched rows from the...
Date, c.Name, r.Name AS ReferredByName FROM Invoices i JOIN Customers c ON i.CustomerId = c.Id LEFT JOIN Customers r ON c.ReferredBy = r.Id ORDER BY i.BillingDate; This question simply tests the candidate’s ability take a plain-English requirement and write a corresponding SQL query...
These kinds ofSQL interview questionsconfuse the candidate at times. So, coming to the question, there are three different kinds of operators available in SQL. They are: Arithmetical operators Logical operators Comparison operators 4) Are the terms zero or blank space the same as that of NULL ...
SQL commands There are five main categories for the SQL commands: DDL –Data Definition Language– defines and alters the database schema; DQL –Data Query Language– performs the query operations on the data within schema objects; DML –Data Manipulation Language– manipulate the data present in...
PL/SQL supports various data types, categorized as follows: Scalar Types: Single-value types likeNUMBER,VARCHAR2,DATE,BOOLEAN. Composite Types:Collections such asRECORD(custom structures) andTABLE/VARRAY(arrays). Reference Types:Pointers to database objects, likeREF CURSORfor dynamic query processing....
SQL Server books online has enough information on this topic and there is a good white paper available on Microsoft site. 12. Explain the architecture of SQL Server This is a very important question and you better be able to answer it if consider yourself a DBA. SQL Server books online is...
Eventually, in an outer query, apply aWHEREfilter and aCOUNT()function on the result of the subquery. Solution of SQL Interview Question #3 Solution: SELECT department_name, AVG(salaries.salary) AS avg_salariesFROM employeesJOIN salariesON employees.employee_id = salaries.employee_idGROUP BY dep...
Best Interview Question Database PostgreSQL Interview Questionsand Answers PostgreSQL Interview Questions 1. What is PostgreSQL and why it is used for? 2. What are the features of PostgreSQL? 3. How to install PostgreSQL on windows? 4. How to install PostgreSQL on Ubuntu? 5. List data type ...