Amazon (AMZN) Web Services is once again putting pricing pressure on its competitors. The cloud computing company announced it has reduced the pricing on both on-demand and reserved instance pricing for Amazon Relational Database Service (RDS).

According to a blog entry on the AWS blog, Amazon has reduced on-demand prices by as much as 18 percent for MySQL and Oracle BYOL (bring your own license), and by 28 percent for SQL Server BYOL. The rates officially went into effect at the beginning of June.

Although there are other major competitive aspects to cloud, one of the biggest is pricing, and AWS has continued to drive prices down. Much of the time, the cloud company is leading the way with the lowest price and forcing competitors to either match pricing or find other ways to compete. For instance, look at the recent examples of Microsoft cutting pricing for Windows Azure storage and IaaS offerings.

Exact savings depends on the specific regional data center customers choose, with the biggest price cut being in the U.S. West (Northern California) server. For a three-year reserved instance, customers choosing U.S. West (Northern California) will experience 27 percent savings over pricing prior to June 1.

"Although reserved instance purchases are non-refundable, we are making a special exception for one-year RIs purchased in the last 30 days and three-year RIs purchased in the last 90 days. For a limited time, you can exchange recently purchased RI's for new ones," according to the blog.

Pricing is one of the key ways AWS is continuing to stay competitive, and competitors have little choice but to match that pricing if they want to stay competitive.