Regular expression to remove comments from SQL statement

Question

I\'m trying to come up with a regular expression to remove comments from an SQL statement.

This regex almost works:

(/\\*([^*]|[\\r\\n]|(\\*+([^*/]|         


        

Answer 1

In PHP, i'm using this code to uncomment SQL:

$sqlComments = '@(([\'"]).*?[^\\\]\2)|((?:\#|--).*?$|/\*(?:[^/*]|/(?!\*)|\*(?!/)|(?R))*\*\/)\s*|(?<=;)\s+@ms';
/* Commented version
$sqlComments = '@
    (([\'"]).*?[^\\\]\2) # $1 : Skip single & double quoted expressions
    |(                   # $3 : Match comments
        (?:\#|--).*?$    # - Single line comments
        |                # - Multi line (nested) comments
         /\*             #   . comment open marker
            (?: [^/*]    #   . non comment-marker characters
                |/(?!\*) #   . ! not a comment open
                |\*(?!/) #   . ! not a comment close
                |(?R)    #   . recursive case
            )*           #   . repeat eventually
        \*\/             #   . comment close marker
    )\s*                 # Trim after comments
    |(?<=;)\s+           # Trim after semi-colon
    @msx';
*/
$uncommentedSQL = trim( preg_replace( $sqlComments, '$1', $sql ) );
preg_match_all( $sqlComments, $sql, $comments );
$extractedComments = array_filter( $comments[ 3 ] );
var_dump( $uncommentedSQL, $extractedComments );