PHP, MySQL and Case Sensitivity of Field Names

MySQL is always case insensitive for field names (but not table names on *nix).

Now here's the subtlety PHP will adopt what ever case you define in your query so if out of perversity you write your query , :-

"select SuRnAmE from addresses"

Then you will have to remember to use the same messy casing in PHP (known as camel case)

$surname=$row['SuRnAmE'];

so better
"select surname from tbl_addresses"

$surname=$row['surname'];


Play Safe always use lowercase!