MySQL Interview Questions and Answers
MYSQL is one of the most successful and leading pathways toward data administration careers. You will be amazed to know that this database service holds a total of 46.83% share in the relational database market. So to make your career and prepare for interviews in this field would be a good choice. Today we will help with these interviews by providing you with some MYSQL Interview Questions and Answers. MYSQL is one of the most popular database technologies used in the database industry. Popular companies like Microsoft, Amazon, Oracle, and IBM are using this technology on a vast basis to manage and store their data. According to one survey, nowadays more than 90% of organizations are using OSDBMS i.e. Open Source Database Management System. But to handle this database, professionals must know the MYSQL programming language.
|Quick Facts About MySQL
|What is the latest version of MySQL?
|8.0.22 released in 19th October 2020
|When was MySQL first released?
|23 May 1995
|Who developed MySQL?
|What language does MySQL use?
|C and C++ language
|GNU Public License
MySQL Query Interview Questions
SELECT EmpId, Project, Salary, COUNT(*) FROM EmployeeSalary GROUP BY EmpId, Project, Salary HAVING COUNT(*) > 1;
SELECT * FROM EmployeeSalary
SELECT * FROM ManagerSalary
WHERE term is used for filtering rows, and it applies to every row but HAVING term is used to filter groups.
WHERE can be used without the GROUP BY but HAVING clause cannot be used without the GROUP BY.
These are the set of rules applied to columns on the table. It is used to bound the type of data that can go into a table.
Types of constraints
- PRIMARY KEY
- FOREIGN KEY
- Not NULL
SHOW INDEX FROM TABLE_NAME;
select count(*) from TABLE_NAME where 'status' = 1;
HEAP tables are in memory. No TEXT or BLOB fields are allowed inside HEAP tables. They are typically used for high-speed transient storage.
In MySQL, a temporary table is a distinct type of table that approves you to save a transient end result set, in which you can reuse countless instances in a single session. A brief table is created with the aid of the use of the
CREATE TEMPORARY TABLE statement.
It is the best way to upload large CSV files through the LOAD DATA command.
LOAD DATA LOCAL INFILE "your file name" INTO TABLE table name FIELDS TERMINATED by ’,’ LINES TERMINATED BY ’\n’
The degree of a table is the number of columns in the given table. It is also called as Arity. It is the range of entities inside each entity type that can be linked via a given relationship type.
In MYSQL Database, data is stored in tabular form and that is why we also call it a Relational Database Management System. With the help of it, users can develop an infinite number of applications but it is mainly used for web applications. Talking about platforms, it can run on various platforms like LINUX, UNIX, and WINDOWS and is reliable, fast, and very easy to use. We hope these questions will help you to clear your core concepts regarding MYSQL. Let us help you with some short and important tips which might help you with your interviews-
- MYSQL is a programming language, so always avoid YES and NO answers.
- If you don’t know the answer, simply say I don't know rather than pretending you know.
- Always carry a pen and notepad with you.
- If you are stuck somewhere don’t panic, just stay calm and think out loud.
- Go with the expectation that you will reject a lot, as “Failure is the key to Success”.