Question

is there a performance difference between

$a = mysql_query("SELECT * FROM table WHERE id = 1 AND text = 'test'");

and

$a = mysql_query("SELECT * FROM `table` WHERE `id` = '1' AND 'text' = 'test'");

Answer 1

No, backticks do not affect performance. They are used to escape reserved words, but you are free to wrap all your table and column names with backticks if you prefer.

I’m not sure if it is a typo, but your second example is not equivalent to the first one when it comes to the 'text' = 'test' part in the WHERE clause. The first will try to match the 'test' value to the text column, while the second one will always return false since 'text' is not equal to 'test'.