Improper Neutralization of Special Elements in Data Query Logic

// SimpleDB's select expression is a query language, so a value spliced into it is injected
// exactly as it would be into SQL.
class BillingServlet extends HttpServlet {
  @throws[IOException]
  override def doGet(request: HttpServletRequest, response: HttpServletResponse): Unit = {
    try {
      val account = request.getParameter("account")
      val credentials = new BasicAWSCredentials("id", "secret")
      val simpleDb = new AmazonSimpleDBClient(credentials)
      val expression = "select * from invoices where account = '" + account

      // VULNERABLE: Improper Neutralization of Special Elements in Data Query Logic
      val page = simpleDb.select(new SelectRequest(expression))
      // VULNERABLE: Improper Neutralization of Special Elements in Data Query Logic
      val consistentPage = simpleDb.select(new SelectRequest(expression, false))
      val builder = new SelectRequest()
      // VULNERABLE: Improper Neutralization of Special Elements in Data Query Logic
      val builtPage = simpleDb.select(builder.withSelectExpression(expression))

      val fixed = "select * from invoices where account = '000123'"
      val fixedPage = simpleDb.select(new SelectRequest(fixed))
    } catch {
      case _: Throwable =>
    }
  }
}