how do I SUM column values if the name of the column contains a word
The maximum number of columns in a table is 1024 so you can’t keep adding columns for every brand/item permutation that ever michael kors handbags occurs.
If a brand makes bags and shoes you michael kors handbags will be repeating the information about the brand multiple times. Any time such information is repeated there is a possibility that slight differences and anomalies creep in. Additionally if a brand changes their name you need to update the column and all code you have that references it.
You can’t do simple calculations such as summing all bags without hard coding all the permutations and remembering to update that code when you add a new brand.
You can michael kors handbags ‘t do some queries at all (or at least not without great difficulty) such as bring back the name of all brands that supply michael kors handbags shoes.
Well, I wanted to try to solve this as asked as an exercise for myself because I’m learning SQL in more depth. I think the problems with the given schema are well enough documented for me to not say anything else about that.