SQL Developers Hiring Guide

A domain-specific language used for managing data in relational database management systems

Every app and website on the Internet today is full of data. Whether that data is concerning personal and account information, money in a bank account, or status updates on a social network, it’s all data that requires storage in some capacity. This is where databases come into play. 

Databases not only store data but also provide functionality for adding, modifying, and querying said data. They come in many forms, with relational databases ranking as one of the most used. Most databases come with a querying language used to interact with these databases.

The most popular language used for these tasks is SQL. Designed entirely for accessing databases, SQL stands for Structured Query Language. It allows developers to create tables, change data, and retrieve other data. 

According to the American National Standards Institute (ANSI), SQL is the standard language for relational database management systems. Some of the most common relational database management systems to use SQL with include MySQL, Oracle, Microsoft SQL Server, Sybase, Access, and many others.

  • Hiring Guide

  • Interview Questions

  • Job Description

Data is one of the most valuable assets in today’s tech world. Every company across every industry runs on data in some way, which means they need to create an organizational method that makes it simple, easy to sort, and relevant. Databases help companies keep their enormous amounts of data organized and accessible at all times. This is where SQL comes into play. 

Professional SQL developers are in high demand as the need for data visibility and organization never ends. Companies continually push to implement their strategies for successful digital transformations while striving to become data-driven organizations. 

While many developers specializing in full-stack or backend development typically have some knowledge base for handling databases, experienced SQL developers make incredibly valuable members of a development team.

While SQL is a relatively straightforward declarative language, SQL developers must possess a thorough technical background. Typically, technological requirements vary across organizations. Some companies will require their dev teams to manage and support applications written in Java, C++, or C#, while others will require a variety of other languages. It’s necessary for SQL devs to have experience in these languages to understand the applications they must support as well as a solid knowledge base of PHP.

Having not only awareness of a variety of databases as well as the skills to manage them via SQL is also a must-have skill for SQL developers. Devs have the ability to use declarative SQL statements to optimize nearly any database but they should also have enough skills with said database to know how to best do so. Although many developers think of SQL as an old-fashioned technology because of its relatively simple syntax, its functionality continually proves otherwise on a daily basis. 

What’s the difference between SQL and MySQL?

MySQL is a Relational Database Management System and one of the first open-source databases available on the market. SQL is a language used to operate a database such as MySQL to access, update, manipulate, and query data inside of the database. SQL is the querying language to the actual software that is MySQL.

What are the different subsets of SQL?

  • Data Manipulation Language or DML - This language allows developers to access and manipulate data while also allowing for insertion, updates, deleting, and retrieving data from the database.
  • Data Definition Language or DDL - It allows devs to perform a variety of operations on the databases, including CREATE, DELETE, and ALTER objects.
  • Data Control Language or DCL - This allows for the controlling of access to the database on a permissions level.

What’s the difference between a clustered or non-clustered SQL index?

A clustered index alters the storage method of records within the database and sorts out rows by column. This is useful for the easy retrieval of data from the database while also working faster than within a non-clustered index. A non-clustered index creates a separate object within a table that then points back to the original table rows after a search. A table may only have one clustered index but many non-clustered indexes.

What is Denormalization? 

Denormalization is the technique used to access data ranging from higher to lower forms of a database. This is a useful technique for database managers to help increase the performance of the entire infrastructure of a said database by introducing redundancy into a table. Database queries used to combine data from various tables into a single table add redundant information into one table.

Define local variables, global variables, and their differences.

Global variables are usable and exist throughout a program. The same variable declared in a global format isn’t used in functions and isn’t created when calling said function. Local variables exist within the function. They aren’t known to other functions and can’t be used or referred to. Functions create variables when called. 

We are in search of an experienced and highly skilled database professional specializing in SQL. The right candidate will have extensive experience in the management, organization, planning, and responsibility of managing large databases while creating custom reports, queries, and procedures. They will be responsible for the designing of databases and ensuring their reliability, stability, and overall performance. 


  • Develop high-quality and dependable database solutions
  • Build useful reporting deliverables
  • Manage, organize, and update all databases
  • Analyze existing SQL queries to identify and execute performance enhancements where applicable
  • Suggest and utilize new queries
  • Support the processes used to identify, capture, and store data in a data warehouse structure
  • Design, maintain and enhance all other data models to support business initiatives 
  • Manage model extensibility with performance

Skills and Qualifications 

  • Bachelor’s Degree in Computer Science (or similar field) or 5+ years of comparable work experience
  • 5+ years of SQL experience
  • 5+ years of experience in data warehousing and business intelligence reporting
  • Strong knowledge of MySQL, Oracle, and other top databases

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