Is it enough to install SP3 of SQL Server 2005 alone?

I installed SQL Server 2005, and I want to install service packs, I have service packs 1, 2, 3, but I want to know, Is it different to install just service pack 3? or I should install first SP1, the SP2 and finally SP3?

The service packs are cumulative, read here. I think this belongs on SF though.

Microsoft SQL Server 2005 Service Pack 3 (SP3) contains hotfixes that were included in cumulative update packages for SQL Server 2005 Service Pack 2 from cumulative update package 1 to cumulative update package 9, and fixes to issues that have been reported through our customer feedback platforms. It also includes supportability enhancements and issues that have been reported through Windows Error Reporting.

Install service pack 3. If it wants you to install the rest, it will tell you.

I think the Sql Server team understands this situation may happen and have taken steps to account for it.

Or, better yet, go to Windows Update. Hurr.