title: How do I get query for products added in last 30 days (HSQLDB)
body: <p>Before anyone comments, I must use HSQLDB RDBMS; it's for university java project. My question is how would I get list of invoices created in last 30 days</p>
  
  <pre><code>CREATE TABLE Invoices(
      rid INTEGER GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
      invoicedate TIMESTAMP NOT NULL);
  </code></pre>