Placeholders are definitely the way to go. However there is another approach that can be useful for situations where you can't use palceholders. The only example that comes to mind of a time where you can't use placeholders is "selet * from foo where bar in (?)" where you want to specify a list with an unknown number of elements for ?.

The DBH quote function will quote a variable apropriately for the DB that your handle is connected to, escaping all necessary metacharacters, etc....

my $s=$dbh->quote($a);
[download]

---

---

• Are you posting in the right place? Check out Where do I post X? to know for sure.
• Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:

  <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>

• Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
• Want more info? How to link or How to display code and escape characters are good places to start.