This is a hard problem to solve, and the best approach depends very much on the scope of your task. If you have a small database table with a limited number of columns, you might get away with some basic pattern matching techniques. If it is more complex than that, you might have to do a full-scale syntactic analysis of the question. This also depends on the variations of possible question types.
Assuming a limited set of variables and variants, you could set up something like:
How many X did Y produce/How many X were done by Y/What is the number of X for Y
where you have two variables to fill from the pattern, which you then use in your query:
select sum(X) where producer == Y
(Or whatever format your query has).
The advantage of this is that you don't need to be a linguistics expert to maintain/expand the system, and you can just add more patterns to it if necessary. You might have to map some terms onto synonyms to get the right column headings/labels out of it. But this approach is not very hard to implement, and you should have a basic system up and running fairly quickly. You then have to see/test what questions your users are asking, and expand the pattern inventory accordingly.
The disadvantage is that you might end up with a long list of patterns, and there could be some which are conflicting, ie the same pattern with different variables will ask for a different kind of result. If that turns out to be a problem, you might have to look for a more powerful approach.
