SQL Question

[WhiteDarkrai]

I want to take all of the wotlk items and put them in a tbc database. How do I go about doing this?

Also, in 2.4.3, attack power and spell power are spells unlike in 3.3.5+ they are stats. Is there a way in the 2.4.3 DB/core to make items use spell power and attack power as a stat instead of a spell?

[Insanity]

I would take that question to the forum of your database (trinity, udb, etc).  Most of the forums have a tbc version and they could better help you with that.
Basically you need to go through the item tables and fix which field differ between tbc and wotlk, don’t forgot to check the displayids and see if the models are present in the tbc dbc.  I’m sure there are other things in the dbc to take care of but that’s another topic…also best asked at the db forum sites

As for your second question the core's forum could help you more (that would be trinity, mangos, etc).  I assume you  would have to convert the numbers back to the tbc format unless you are comfortable with updating the portions of the core that handle items and their effects.