Temporary Columns

[Diego Villamil]

Dear MySQLers,
This is my first post.
I learnt about creating temporary tables and was trying to implement it.
I get an error because the original table on which my temporary one is based at will be used in my query. So it seems that I cannot open it twice.

What I thought I need is to store a temporarily column on such table. That way I can reference that column several times in my query without storing it permanently. How can I do this? Would this be the best solution?

Thanks,
Diego