Does what SQL in Access speed up queries?
The default underlying data storage method of Access is JET, to manipluate data in JET you use SQL.
If ypou mean does using a server based SQL engine, such as MS SQL Server, or MySQL, or whatever, then it depends on the application. how many users there are, where the data is stored, what sort of search or filtering you are going to do, and perahps more importantly how your Access application is designed.
A well crafted Access application serving upto say 25 users doing mainly data entry will probably be as rapid as a server based SQL engine. A poorly crafted Access application talking to server SQL engine will probably run slower than using native JET.
However a well crafted Access app, using a server will generally run a lot faster than the same app runnning on JET. It depends how you design and implement the application. The advantages of the server storage medium are also in areas such as concurrency, supporting more than 255 users, better operational availability.
However it doesm't alter the fact that Access is a means of creating a front end (the user interface) and not itsefl a means of storing data
I'd rather be riding on the Tiger 800 or the Norton