A couple of weeks ago, I mentioned a way to improve the performance of MySQL queries by avoiding the use of the lower() function to provide case-insensitive matching. (I suggested the use of LIKE without wildcards.) A couple of people have written to mention that by default, the = operator is not case sensitive in MySQL, so an expression like 'Houston' = 'HOUSTON' will be a match. For other databases, the LIKE thing is probably still good advice.