What are the common pitfalls when using regular expressions in PHP for search functionality?

Common pitfalls when using regular expressions in PHP for search functionality include not properly escaping special characters, not handling case sensitivity, and not considering performance implications for large datasets. To solve these issues, it is important to use the appropriate functions like preg_quote() for escaping special characters, the 'i' flag for case insensitivity, and optimizing the regular expression pattern for better performance.

// Example of using preg_quote() to escape special characters
$searchTerm = "example.com";
$escapedSearchTerm = preg_quote($searchTerm, '/');
$pattern = "/$escapedSearchTerm/i";

// Example of case-insensitive search using the 'i' flag
$searchTerm = "example";
$pattern = "/$searchTerm/i";

// Example of optimizing the regular expression pattern for performance
$searchTerm = "example";
$pattern = "/\b$searchTerm\b/i";