Search db from aps.net...exclude data in other tables

3 tables apply here:
1) tblChinaProvinces
2) tblChinaCities (linked to province table via prov_id)
3) tblCompanies (id, name, city_id)

Most company names include the city and or province it's located in. Typical naming trend here in China.

Example: User search for company using the keyword "shang" will return all companies who's name contain cities/provinces like "Shanghai", "Shangdong" etc. and this result into really long search results. (basically "

Code:

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SELECT * FROM tblCompanies WHERE name LIKE '%shang%'

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)

So, without making the search operation hell slow, how can I exclude companies, who's names include entries in the city and province tables?

So far, in my head, everything I come up with will obviously slow things down, but then my SQL knowledge are pretty basic, so was hoping one of you guys can give me some idea.