Custom Field Query

I sure hope somebody can help me through this one (Please!) …

I am trying to query the wp_postmeta table for multiple values. For example, I am trying to get the results for entries in the table that have a meta_key of state, a meta_key of city, a meta_value of washington, and a meta_value of Seattle.

I’m storing data in custom fields, and now I need to query it to get the entries that are basically in Seattle, WA. This would change for each query.

The problem is that a meta_key can’t have a value of both “state” and “city”…the same problem exists for meta_value.

I’m creating a website to store information relative to location. What I’m doing is extending the search capabilities to search within a particular city and state, which is why I’m using these custom fields in the first place… ??

I’m using the posts_where filter to run my custom query as noted at: https://codex.www.ads-software.com/Custom_Queries, but the example that is given assumes that the information is located in a separate table (presumably for the plugin doing this work), not in the wp_postmeta table, which is where I am storing this information…

You can see the SQL select statement and the search form at: https://www.visitwise.com/?s=Thai&whichCity=mesa&whichState=arizona&key=state

Again, thanks in advance for any guidance you can offer, I’m at my wits end with this one…

Thanks!