When working with customer data or upon time series data science projects, you’ll often find the need to calculate the difference between two dates in your MySQL queries. The MySQL...
When working with customer data in ecommerce it’s very common for data scientists to need to add and subtract from date values directly within MySQL queries. For example, you might...
The SQL CASE statement is used for flow control, much like an if, then, else statement. If the statement finds a match on the chosen condition it will return the...
Most SQL databases store dates in the datetime format. This is really useful because MySQL, and other SQL dialects, make it very easy to convert datetime objects to a wide...
MySQL includes a large number of string functions and operators that you can use in SQL statements to both query data and reformat column values. In this simple example, I’ll...
When you create an SQL SELECT statement, the data probably won’t be returned or sorted in the order you want, so the ORDER BY clause is used to control the...
The SQL GROUP BY clause groups row-based data into aggregated data, reducing the number of rows in the dataset, and is commonly used to perform aggregate calculations.
In SQL, when you want to SELECT data that lies between two values, there are a number of different SQL operators you can use to return the correct data. However,...
The SELECT statement is the most simple of all SQL queries and allows you to retrieve the precise data you want from one or more tables, or even databases. In...
SQL is one of the most widely used languages in data science so it’s important to know at least the basics required in order to fetch the data you’ll need...
If you need to create a backup of a remote MySQL database, you can use the mysqldump command. The mysqldump application is known as a client utility and installed alongside...
If you regularly work with ecommerce data, you’re likely to have encountered PHP serialized arrays or objects. Serialization is a process used to take a complex data structure, such as...
If, like me, you’ve come from a background where you made heavy use of SQL, then getting to grips with filtering, subsetting, and selecting data in Pandas can be a...
SQLite is a relational database management system (RDBMS) that is easy to access within Python and other languages. Unlike MySQL, PostgreSQL, and other databases, SQLite uses a serverless design, so...
For years, I used to spend much of my time performing Exploratory Data Analysis directly in SQL. Over time, the queries I wrote became very complicated, and it was often...
Google BigQuery is a “serverless” data warehouse platform stored in the Google Cloud Platform. The serverless approach means you don’t have to maintain a server yourself and Google looks after...
Many MySQL databases are configured to accept connections from other servers on the local network and will reject connections from remote machines. Ordinarily, you could work around this by creating...
Like most people who work in ecommerce data science, I regularly need to access data stored in a database - usually MySQL or MariaDB, but sometimes also MSSQL. Although it...
