Introduction to MySQL Interview Questions and Answers
The following article provides an outline for MySQL Interview Questions. MySQL is an open-sourced and most commonly used Relational Database Management System (RDBMS). It gives its extensive support and compatibility with Linux, macOS, and Windows operating systems. It is mainly one of the most common extensions of SQL. Written in C and C++, it is the central component of a LAMP (Linux, Apache, MySQL, and Perl/PHP/Python) stack.
Below are some of the essential features:
- It supports DDL (data definition language) concerning InnoDB Storage Engine.
- It provides support to Information Schema.
- There is SSL support present.
- It has an embedded database library.
- It has built-in replication support.
- It provides cross-platform support.
Now, if you are looking for a job related to MySQL, you need to prepare for the 2023 MySQL Interview Questions. Every interview is indeed different as per the various job profiles, but still to clear the interview, you need to have a good and clear knowledge of MySQL processes. Here, we have prepared the important MySQL Interview Questions and answers which will help you get success in your interview.
Here are the 10 important MySQL interview questions and answers that interviewers frequently ask:
These questions are divided into two parts as follows:
Part 1 – MySQL Interview Questions (Basic)
This first part covers basic Interview Questions and Answers
Q1. What do you mean by MySQL Workbench?
MySQL Workbench is essentially the officially integrated environment for MySQL that is implemented to control MySQL and visually design database structures graphically. It gives users the provision to prevent the functionalities as per their requirements. It is mainly available in two versions, one is the open-source free community edition, and the other one is the proprietary standard edition.
Q2. Explain MySQL Database Workbench?
MySQL Database Workbench is the software application developed by Upscene Productions, primarily used to develop and administer various relational databases using SQL.
It provides support to the below-mentioned relational databases:
- MySQL Database
- Microsoft SQL Server
- Oracle Databases
- Nexus DB
- Inter Base
- SQL Anywhere
Q3. What do you mean by Joins, and explain different types of MySQL Joins?
In MySQL, joins are primarily used to retrieve records from two or more tables using some related common fields or keys among the selected tables. There are mainly three types of joins present in MySQL.
a. Inner Join: In the case of an inner join is used to fetch the list of rows when there is a match among the specified tables. It is the default join type.
SELECT column_name(s) FROM table1 INNER JOIN table2 ON table1.column_name = table2.column_name;
b. Left Join: In the case of left join, it returns all rows from the left table even if there is no match in the right table.
SELECT column_name(s) FROM table1 LEFT JOIN table2 ON table1.column_name = table2.column_name;
c. Right Join: In the case of right join, it returns all rows from the right table even if there is no match in the left table.
SELECT column_name(s) FROM table1 RIGHT JOIN table2 ON table1.column_name = table2.column_name;
Q4. Explain different types of MySQL functions.
Given below are the different types of MySQL functions:
- MySQL String Functions: Examples are – INSERT, CONCAT, FORMAT, INSERT, LENGTH, LEFT, FIELD, LTRIM, TRIM, UPPER, etc.
- MySQL Numeric Functions: Examples are – AVG, DIV, EXP, MAX, MIN, POWER, TRUNCATE, etc.
- MySQL Date Functions: Examples are – ADDDATE, ADDTIME, DATE, MONTH, MINUTE, etc.
- MySQL Advanced Functions: Examples are – BIN, CASE, CAST, DATABASE, IF, ISNULL, VERSION, etc.
Q5. Explain the differences between primary key and foreign key constraints.
A primary key constraint uniquely identifies every record in a table. It always contains unique values and never contains any NULL values. Below is the syntax for the same, whereas foreign key constraint is used to link between two tables. It is the field that refers to the primary key of the other table.
Part 2 – MySQL Interview Questions (Advanced)
Let us now have a look at the advanced Interview Questions.
Q6. Explain the differences between delete, drop, and truncate.
Find below the fundamental differences:
- Delete: Delete is a DML statement that can be implemented using the ‘where’ clause and rolled back.
DELETE FROM table_name WHERE column_name = column_value;
- Drop: Drop is a DDL statement that can’t be rolled back. By using this, the entire table and all its constraints and privileges will be removed.
DROP TABLE table_name;
- Truncate: Truncate, a DDL statement, removes all the rows from a table, but it leaves the table’s structures, constraints, and indexes unchanged.
TRUNCATE TABLE table_name;
Q7. Explain the main difference between InnoDB and MyISAM.
In the case of InnoDB, it is used to store the tables in the tablespace, whereas, in the case of MyISAM, it stores each MyISAM table in a separate file.
Q8. Explain different types of tables in MySQL.
Find below different types of a table in MySQL.
- InoDB: This table type mainly enhances and supports transactions using COMMIT and ROLLBACK commands.
- HEAP: This type of table is primarily used to process data access faster than the normal speed. But on the downside of it, all data will be lost in case of table deletion.
- BDB: This type of table also serves transaction support implemented using the COMMIT command, but its processing speed is much slower than that of InnoDB.
Q9. Explain MySQL transaction properties.
The transactions mainly consist of four properties.
- Atomicity: The property mainly controls all operations and ensures that all transactions are completed.
- Consistency: This ensures the database changes according to the successfully committed transactions.
- Isolation: This is primarily used to control independent transactions.
- Durability: It controls and measures the effect and presence of committed transactions in case of system or database failure.
Q10. Explain a few pros and cons of MySQL.
Given below are a few pros and cons:
- Compared to its competitors, the MySQL products are more stable and solid.
- It is easier to use from the user experience perspective.
- It is open-source and thus is free to use.
- There is significant and extensive community support exists for MySQL.
- There is sometimes, a bit of performance scaling issues exists in the case of MySQL.
- A lack of a community development approach sometimes causes development progress to lag.
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