Question

I would like to know if there is a better way than :

REPLACE(REPLACE(REPLACE(REPLACE(REPLACE('p%a_t*er?', '\\', '\\\\'), '%', '\%'), '_', '\_'), '*', '%'), '?', '_')

To transform standard search patterns * and ? to the LIKE equivalents % and _ in MySQL ?

Answer 1

There isn’t a shorter method to perform multiple-character replacements directly in MySQL. There are alternatives such as User-Defined-Functions (UDFs), but I’m doubtful that any would be beneficial to your exact purpose.

My suggestion would be to perform the text replacement prior-to querying the database, if acceptable.

In PHP, this could be done with:

$searchQuery = $_GET['q'];
$searchQuery = str_replace(array('*', '?'), array('%', '_'), $searchQuery);
// perform your query as normal

In ASP, you could try:

string searchQuery = Request.QueryString["q"];
searchQuery = searchQuery.Replace("*", "%").Replace("?", "_");
// perform your query as normal

Though, both method aren’t super-short, they do make it a little easier to read and also won’t add any time to your db-query. Also, doing the replacement prior to the query will allow you to replace before the string is sanitized so you won’t need to replace the \ as you do in your existing query – which saves you one replacement!