first, sry for my english!
I have to copy one attribute column of an attribute table (>200k values) in the same attribute table. This attribute column has around 40 different values, but for the copy I just need around 5 defined values. All other values have to been deleted. What is the fastest way to do this for big data like this?
Second problem: I have to rename (shorten) this 5 values in the new column ot the attribte table, what is the best way to do this?