I'm doing an upgrade for an older web app. As expected it has the support of older mysql functions (mysql) which requests to replace it with mysqli. Everything goes fine, except when searching for the function "mysql_lookup" and its relations to mysqli.. But even after browsing the web and this forum, I couldn't find any answers that would help or at least suggest how to solve this. Anyone with this experience and solution?
The mysql_lookup function is not part of the PHP mysql interface.
That function must be defined somewhere in your application, or in a library used by your application. You'll need to locate that function, see what it does, and probably reverse engineer it.