Learn SQL

Having knowledge of databases is crucial if you want to explore a career in data. Whether you want to be a data scientist or an engineer, databases will come up at some point. If you want to work in data,…

SQL is a leading programming language in the IT industry and is quickly becoming a high-demand skill in tech jobs. It is a simple language used to query and manipulate relational databases, such as SQL Server and the Oracle database.…

SQL is an acronym for Structured Query Language. SQL is a computer language that allows users to navigate, store, manage, and retrieve data from relational databases. If you’re interested in a career as an SQL database administrator or business intelligence…

A firm understanding of SQL terminology is key for anyone breaking into the tech industry. SQL is one of the most used programming languages amongst software developers. Our list of SQL terms will give you the groundwork you need to…

SQL is worth learning because it’s a programming language that’s in-demand not only in the tech industry but also in other sectors that need technology. For this reason, most software developers who know SQL earn respectable salaries. Is SQL worth…

Structured language query, popularly known as SQL, is one of the most popular domain-specific programming languages in the technology industry today. According to Statista, MySQL is the second most popular database management system worldwide. Programmers use different tools to execute…

GraphQL is an efficient query language for APIs. If you are looking for an alternative query language to Oracle PL/SQL or Apollo, GraphQL might be an ideal option for you. As with every developer tool, there are pros and cons…

Modern businesses employ data analysis to make business decisions. This is made possible through database management systems like MySQL. MySQL is an open-source relational database system that stores a collection of data items with pre-defined relationships. According to PayScale, the…

SQL is a critical programming language that makes it easier to interface with databases and format a management information system. SQL Server Integration Services come in handy for large organizations with a lot of data to manage and store. It…

When was the last time you sent a message through Facebook? Have you recently used a “smart” appliance at home? In both examples, databases are required to store information. NoSQL databases are commonly used in these cases.  NoSQL, or “not…

Have you ever wondered what happens to data that is collected by a website? Every time the front end of a website collects data, it needs a place to store it. This place is called a database.  One type of…

The SQL CREATE TABLE statement adds a table to a database. Using this statement, you can specify the names of the columns in the new table and the types of data each column can store. You can also state any…

The SQL OR statement returns records who meet one of many specified conditions in a WHERE statement. The AND statement returns records who meet all the specified conditions. Both clauses use the syntax: WHERE condition AND/OR condition...; SQL WHERE statements…

PostgreSQL is an open-source relational database management system developed by a worldwide team of volunteers. No single corporation or private entity controls PostgreSQL and its source code is available free of charge. PostgreSQL is one of the oldest relational database…

An SQL subquery is a query inside another query. It is used in the WHERE or HAVING clause of an SQL statement. Subqueries let you specify the results of one query as an argument in another query. When you’re writing…

An SQL alias is a reference name for a table or a column. They are used to shorten your queries if you have long table names. Both table and column aliases are defined using the AS keyword. An alias lasts…

An SQL LEFT JOIN is a type of SQL join. This join returns all the tables from a specified "left" column and the corresponding rows that match a particular condition in the "right" column. In many cases, when you’re writing…

The SQL ORDER BY statement determines the order in which records are returned by a query. You can return records in ascending or descending order by the value of any column in the table. Ordering query results makes it easier…

The SQL INNER JOIN statement returns rows with exact values in two columns across two tables. You can join a table across one or multiple columns. JOIN statements connect two database tables and compare their contents. There may be times…

SQL aggregate functions retrieve information about the data in a database. You can use COUNT to find out how many records are in a database, for instance. Accepted aggregate functions are: COUNT, MIN, MAX, AVG, and SUM. There are occasions…

The SQL GROUP BY statement appears in aggregate functions. It is used to collate the data you select from a query by a particular column. You can specify multiple columns which will be grouped using the GROUP BY statement. When…

The SQL LIKE operator uses wildcards to find data similar to a particular pattern. You can use an underscore to substitute for a single character or a percentage sign to substitute zero, one, or multiple characters. Have you ever wanted…

The SQL BETWEEN keyword retrieves values that fall within a particular set of values. It is often used to retrieve values between two dates or numbers. This keyword is used in WHERE clauses. The syntax for this keyword is: "BETWEEN…

The SQL IN keyword lets you select values that appear in a range of values. You can specify a query inside an IN statement to search for records whose column has a value in the result of a query. The…

The SQL ALTER TABLE statement adds, changes, or removes a column in a table. This statement lets you modify a table after it has been created, even if the table stores records. You may decide that you need to make…

The SQL WHERE clause limits how many records are returned or affected by a command. It is used with the SELECT, UPDATE, and DELETE clauses. You can use the AND keyword to specify multiple conditions which you want records affected…

The SQL not equal operator is represented by <>. This operator lets you select rows from a database that do not meet a particular condition. The != operator is used in a WHERE statement. The != operator can be used…

The SQL LIMIT statement restricts how many rows a query returns. A LIMIT statement appears at the end of a query, after any ORDER BY statements. You can start a LIMIT statement at a particular row using the offset argument.…

The SQL DELETE statement deletes a row from a database table. You can use the WHERE statement to specify which records should be deleted. If you do not specify a where statement, every row in the table will be deleted.…

Working with a greenfield project means you are starting from scratch. It is common to be a part of a team that has to make the choice of what type of database to use. If having access to available data…