14 examples of how testers can answer SQL interview questions
For a job as a SQL tester, you need to know a lot about data science, which is a very broad field. Some job interview questions are more common than others, but database testing questions are much more in-depth. So, if you want to make a good impression on the interviewer, you should practice and get ready. 14 examples of how testers can answer
This article will give you examples of SQL interview questions and sample answers to help you get ready for your next SQL tester interview.
14 SQL tester interview questions and example answers
Here are some common interview questions asked of SQL testers and some examples of how to answer them:
What does it stand for?
“The American National Standards Institute came up with Structured Query Language, which is a language for databases. It is used to talk about databases and make them.” SQL helps software applications get, change, add, and get rid of data. SQL lets you run queries, add and change records, create and delete databases and tables, and do other things.
DBMS stands for “database management system.”
“DBMS stands for “database management system.” This is a program that helps maintain, monitor, create, deploy, and control how a database is used. It also works as a file manager for the data in a database, no matter how big or complicated the database is.
What does a SQL table do?
“The table is a model made up of a set of records that are set up in rows and columns. The number of records that can be set by rows in a table has no clear upper limit.”
What are the different clauses in SQL?
“An SQL clause is used to limit the results of a query to only those that meet certain conditions.
The GROUP BY clause comes after the WHERE clause and before the ORDER BY clause in a SELECT statement. It is used to group together data that is the same.
In a GROUP BY clause, HAVING is used to set a search condition. A WHERE clause can be used instead of a GROUP BY clause if there isn’t one.
ORDER BY: Sorts the result set in either ascending (the default) or descending (using the DESC keyword) order.
WHERE: Used to define the conditions for the records to be extracted.”
When testing a database, what should you look for?
“Every function should be tested, such as field size validation, constraints, indexing, stored procedures, data validity, data integrity, triggers and functions, and database performance. But more care should be taken to make sure that new and deleted records are correct.”
What does testing that is based on data mean?
“Data-driven testing is an automation framework in which test data is kept in a table or spreadsheet. Input values are read from data files and saved in different test scripts. This is helpful because it keeps you from having to test each set of data separately, which can take a lot of time.
The framework keeps the data separate, and the same test script can be used to get results for many different sets of test data. The data you put in can be saved as XLS, XML, CSV, or database files. There are four different types of tests that use data:
- Dynamic test data is entered through the keyboard to retest an application with new input values to make sure the original calculation was right.
- Flat files (.txt,.doc): Testing the data again with a flat file.
- Front-end object: Values like list, menu, table, data window, and ocx are taken into account when making automation scripts.
- Excel: “This test runs the script with multiple inputs that are saved in an Excel sheet.”
What are “JOINs” in SQL, and what are the different types of “JOINs”?
“A JOIN is a keyword that is used to get data from multiple tables based on how their fields relate to each other and then show the data as a single set. Some of the most common types of JOINs are INNER JOIN, OUTER JOIN, LEFT JOIN, and RIGHT JOIN.
What does DML stand for?
“Data manipulation language” is what DML stands for.” DML is a computer programming language that makes it easier to choose, add, take away, and change data in a database. DML is like SQL in that it lets users get and use information from a relational database.
What are DCL commands?
“”Data Control Language” is what “DCL” stands for. It is a part of SQL that controls how people can get to the information in a database. DCL commands come in two types.
The database is open to the users.
Revoke: Don’t let people into the database anymore.”
10. Does QTP support SQL queries?
“QTP doesn’t have built-in database connectivity, but you can connect to and interact with databases using ADODB objects and the VBScript programming language. This can be done in four ways:
- Connection: This makes a connection to a database.
- Command: Sends out a SQL command.
- Finds the right column in a record’s fields.
- Recordset pulls information from a database.”
11. How do you do data-load testing?
“You will need access to both the source database and the database you want to change.
First, make sure that the source database and the destination database can work together by using the DTS package.
- Then, open SQL Enterprise Manager and run the DTS package that goes with it.
- Look at the information in the Source column and the Target column.
- Look at how many rows both Source and Target have.
- Update the source database, and then make sure the changes are reflected in the destination database.
- Seek out NULLs.
- Last, check how busy the database server is and how long it takes to answer queries.”
- What is retesting, and how is it different from testing based on data?
“Retesting means to run the same test again, but with different values for the inputs. This helps find and fix the problem. Retesting is different from data-driven testing because it is done by hand and uses a new set of test data. On the other hand, data-driven testing is done automatically and uses more than one set of test data to test the application.
What does it mean to test for performance?
“Performance testing is a highly specialized way to test software. It helps find out how fast, sensitive, and stable a system is when it is under a lot of stress.”
What are SQL’s constraints?
“Constraints are statements that tell all records in the table what the rules are. Stopping any action that goes against a constraint. With the CREATE TABLE or ALTER TABLE statement, constraints can be set when the database is created or after the table is created. In SQL, there are five main kinds of restrictions.
- NOT NULL: This means that the column must have a value and can’t be left empty.
- UNIQUE: Makes sure that every row and column has a unique value and that no value appears in more than one row or column.
- With NOT NULL and UNIQUE constraints, PRIMARY KEY is used to find a specific record that hasn’t been duplicated.
- FOREIGN KEY: Used to make sure that the data in the table is correct and to match the value in one table with the value in another table by using PRIMARY KEY.
- CHECK is used to make sure that certain conditions are met by the values in the columns.
How to prepare for a job interview in SQL
Follow this rule to get ready for your next SQL interview:
- Learn as much as you can about the company. Find out how it is run, what its values are, and what its goals are. Check out the company’s website, social media accounts, and any press releases that are out there.
- Make sure you have the right skills for the job. If it has been a long time since your last interview, you might want to brush up on your SQL skills and come up with an impressive answer to show the interviewer that you are committed to always getting better and learning new things.
- Find out what SQL interview questions are. Look at the answers that other people have given to common questions and come up with your own short answers that show how much you know.
- Take notes, ask your mentors and coworkers for tips and advice, and practice speaking and standing in the most confident and friendly way.
- Practice by saying your answers out loud or asking a friend to give you feedback. Practicing the interview can help you feel more comfortable during the real one, and it can also help you give much better answers.
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