Though the COALESCE function may seem complex, it’s actually very straightforward and useful. In this short article, we’ll look at several examples of how the COALESCE function can be used to work with NULL values in SQL. The Need for Coalesce Before we dive into the COALESCE function in detail, you should understand how NULL values behave in expressions. Simply put, a value of NULL indicates that there is currently no value for a particular entry in a table column. …

# Tag: AVG

Computing Tardiness: Date, Time, and Interval Arithmetic in SQL In this article, we’re going to discuss some interesting operations we can perform with date-related data types in SQL. The SQL standard, which most relational databases comply with these days, specifies the date-related data types that must be present in relational databases. The most important of such data types are date, time, timestamp, and interval. Here’s a brief rundown of the differences between these data types: date: represents a single day …

The mean (average) is one of the most valuable and most frequently used measures in descriptive statistics. Why is it so widely used, and why is it important to know how to calculate the arithmetic mean? Perhaps the most convincing argument is that the mean is used in virtually every area of life. With the arithmetic mean, you can calculate the average daily television viewing time for citizens of a given country, average volume of coffee drunk by a typical …