SQL Interview Questions for Beginners


What's the difference between SQL, Oracle, MySQL, and SQL Server, and how do you tell them apart?

SQL stands for Structured Query Language, which is a standard for querying databases. Oracle, MySQL, and SQL Server are different database management system implementations or versions that implement the SQL standard and build on it in different ways.

Oracle is aimed at major businesses, while Microsoft owns SQL Server and Oracle owns MySQL, which is aimed at smaller businesses and systems.

What is the difference between SQL and PL/SQL programming languages?

The language SQL is used to query databases. A query, such as SELECT or INSERT, is executed and a result is returned.

Procedural Language/Structured Query Language is the acronym for Procedural Language/Structured Query Language. It is Oracle's procedural language, which is based on SQL. Along with SQL, it allows for additional programming logic to be used.

What exactly is the distinction between SQL and T-SQL?

The language SQL is used to query databases. A query, such as SELECT or INSERT, is executed and a result is returned.

T-SQL (Transact-SQL) is a language and collection of extensions for SQL Server that enables the usage of additional programming logic with SQL.

What is the function of the keyword BETWEEN?

The BETWEEN keyword allows you to verify whether a value in the WHERE clause lies between two other values.

It's the same as determining whether a value is higher than or equal to one value while being less than or equal to another. Here, check the sql scenario based interview questions.

What is the IN keyword's purpose?

You can use the IN keyword to see if a value matches one of a set of values. It's frequently used with subqueries that return several rows.

What is a point of view? When do you think you'd utilize one?

A view is a database object that allows you to view a set of data by running a saved query. A view is created by specifying a SELECT query to be used as the view, and it can then be queried similarly to a table.

A view can be used for a variety of purposes, including improving security, creating a layer of abstraction between the underlying data and applications, and simplifying searches.

What is the difference between a view and one that has been materialized?

A view is nothing more than a SQL query that is saved in the database but does not return any results. This definition of the view's query is run every time the view is requested. The view will load these results if the underlying tables have been updated.

A materialized view is a query in which the results are kept permanently, such as in a table. When the underlying tables are updated, the materialized views are not updated by default.

What is the definition of a primary key?

A primary key is a column (or a combination of columns) in a table that uniquely identifies each row. It's used to guarantee that the values in a column or columns are unique and not NULL.

It's common to do this with a numeric ID field, although it's not required.



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