SQL Query to clear all manufacturers with no products linked

[cbcnz]

Hi All

I have 550 Manufacturers in my database and I want to remove any that have no products, every time I import a csv pricelist it creates new manufacturers if they don't exist so it has built up over the past few months.

 

Also a query to merge duplicate manufactuers would be great :)

 

Sorry I am not very experenced with sql queries at all and I'm sure others will be able to make use of these :)

 

Thanks in advance!