How to dedupe lists in Python with set() and intersection()

When working with Python lists you’ll often encounter times when you need to remove duplicate values present in a single list, remove duplicates found in multiple lists, or identify the...

How to use DATEDIFF() to calculate date differences in MySQL

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...

How to use DATE_ADD() and DATE_SUB() to add and subtract from dates

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...

How to use CASE for flow control in SQL statements

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...

How to use DATE_FORMAT() to reformat dates in MySQL

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...

How to use string functions in SQL statements

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...

How to use ORDER BY to sort an SQL result set

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...

How to use GROUP BY and HAVING in SQL statements

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.

How to use BETWEEN in SQL statements to return data between two values

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,...