As we all know that SharePoint needs SQL server in background one of the important topic is what we need to install it and how. Especially if we have more than one farm intention is to install all SQL with same configuration. Best way to do it by using configuration file.
First we need to copy all installation binaries to location on a local or a network hard drive. Then you need to put configuration file to same location as well. And for a final step you need to run setup.exe with config file parameters.
Dubravko Marak Blog 