Statistic functions that take Null values into account

Statistic functions – that is MAX, MIN, SUM, AVG, VAR, VARP, STDEV and STDEVP – don’t take Null values into account. Usually this isn’t a problem with the SUM function, but it can be an issue with the others. For example, you can evaluate the average value of a group of records keeping Null values into account as follows:

— evaluate the average price of book price– but consider Null values as zeroSELECT SUM(price) / COUNT(*) FROM titles

However, this technique doesn’t let you assume a non-zero price for titles whose price is Null. Moreover, this technique doesn’t easily apply to other aggregate functions, such as VAR or STDEV. You can use a more general approach, based on the ISNULL function. For example, let’s assume that Null should be replaced by $15 when evaluating the average price:

SELECT AVG(ISNULL(price, 15)) FROM titles

Here’s how you can first evaluate the average price on non-Null titles, and then use that value to evaluate the standard deviation:

DECLARE @ave FLOATSELECT @ave = AVG(price) FROM titlesSELECT @ave, STDEV( ISNULL(price, @ave)) FROM titles
Share the Post:
Share on facebook
Share on twitter
Share on linkedin


The Latest

technology leadership

Why the World Needs More Technology Leadership

As a fact, technology has touched every single aspect of our lives. And there are some technology giants in today’s world which have been frequently opined to have a strong influence on recent overall technological influence. Moreover, those tech giants have popular technology leaders leading the companies toward achieving greatness.

iOS app development

The Future of iOS App Development: Trends to Watch

When it launched in 2008, the Apple App Store only had 500 apps available. By the first quarter of 2022, the store had about 2.18 million iOS-exclusive apps. Average monthly app releases for the platform reached 34,000 in the first half of 2022, indicating rapid growth in iOS app development.

microsoft careers

Top Careers at Microsoft

Microsoft has gained its position as one of the top companies in the world, and Microsoft careers are flourishing. This multinational company is efficiently developing popular software and computers with other consumer electronics. It is a dream come true for so many people to acquire a high paid, high-prestige job