SQL is known as an initial language that is responsible for organizing and managing data in a relational database management system (RDBMS). RDBMS is the basis and primary for SQL, and also, for the rest of modern database systems such as MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access. Hire a SQL developer would bring the possibility to get more knowledge about relational databases and also, work on your relevant projects.
Hire a SQL developer, as the most demanding database
According to DV-Engines
report about the ranking of the database trend, the top five popular databases would be regarding Oracle, MySQL, Microsoft SQL Server, PostgreSQL, and MongoDB in order. Although SQL would be in second place in the survey, we shouldn’t forget the undeniable increase of rising in usage and popularity of the SQL, during the previous years.
What are the reasons that clients want to hire a SQL developer?
SQL is a universal database: SQL would be mentioned as the most commonly used database language. Hire a SQL developer also can bring the power to the most commonly used database engines such as MySQL, SQL Server, SQLite, and PostgreSQL
SQL is easy to learn: SQL was built on primary objects. This feature of SQL, would give the possibility to the general users and not even the professional SQL freelance developers, to get the data from it.
But before hiring a SQL freelance expert on a freelancing platform
like Perfectlancer, it would be necessary to be more informed about the right definition of some statements which are relevant to SQL. Hire a SQL expert who would be present along your professional pathway.
The key difference between SQL and MySQL:
SQL has a direct role of assessment and manipulation of the data that are already stored in a database, but MySQL is a relational database management system and provides an organizational database for freelance developers.
The key difference between SQL and NoSQL?
The most of what you will see in SQL are the tables-based databases whereas NoSQL databases have more option to recommend to the users such as document-based databases, key-value pairs, graph databases.
Hire a NoSQL developer with Perfectlancer, if you want to have document-based databases on your projects.
The key difference between SQL and PostgreSQL?
Hire a SQL developer can help for the e-commerce projects to provide different data warehousing solutions for their clients. There would be a mistake to compare the SQL with PostgreSQL. Because PostgreSQL is an advanced version of SQL which provides support to different functions of SQL like foreign keys, subqueries, triggers, and different user-defined types and functions.
The key difference between SQL and SQL server?
SQL Server is a database server that is provided by Microsoft. As an RDBMS tool, SQL and SQL server will execute the SQL statements. By hiring a database server, who would be known as a computer program, you will have the chance for database services to other programs or computers, as defined by the client-server model.
After all, if you want to be sure that your SQL developer that you are hiring, would be the most professional one, you need to just ask some questions about their SQL commands
The most important SQL commands
Select: It makes the command easier to read and understand.
SELECT * FROM table;
e.g. SELECT freelancers FROM table 1
Where: This allows you to apply conditions to the select
SELECT age, name FROM freelancers WHERE age > 18;
Order: It is used to sort the results returned.
SELECT name, age FROM freelancers ORDER BY name ASC (ascending), age DESC (descending)
Join: It is used to join related data stored in one or more tables.
SELECT age, name, occupation FROM freelancers JOIN occupation;
Alias: This is used to temporarily rename a table.
SELECT age AS (Alias) person_age FROM freelancers;
Union: It allows to append rows to each other.
SELECT age, name FROM freelancers
SELECT age, name FROM freelancers;
Insert: It is for inserting data from a database.
INSERT INTO freelancers (name, age) VALUES ('Fra', 20);
Update: it's the command to change specific rows.
UPDATE people SET name = 'Fra', age = 25;
Upsert: It allows to update a record if it already exists.
INSERT INTO freelancers (name, age)
VALUES ('Fra', 25)
ON DUPLICATE KEY UPDATE age = 25;
Delete: It is used to remove records entirely
DELETE FROM freelancers;
Create Table: The create table command is used to create tables.
CREATE TABLE freelancers (
PRIMARY KEY (name)