正则表达式 判断检测sql语句

public static Regex rxColumns = new Regex(@"\A(with\s+(?:(?!\bas\b).)+\s+as)?\s*SELECT\s+((?:\((?>\((?)|\)(?)|.?)*(?(depth)(?!))\)|.)*?)(?<!,\s+)\bFROM\b", RegexOptions.IgnoreCase | R