title: Groovy GString in Sql.execute - text variables are not surrounded by ' and query fails
body: <p>I have the following problem, when I pass GString to SQL.executeInsert, the text variables are not automatically souranded by <code>'</code> so the insert query failes:</p>
  
  <pre><code>String value4fa = "I would like to get know"
  int value4fb = 2
  def query = "INSERT INTO TAB_A (F_A, F_B) VALUES (${value4fa}, ${value4fb})"
  sql.executeInsert(query);
  </code></pre>
  
  <p>If I put <code>'</code> by myself:</p>
  
  <pre><code> def query = "INSERT INTO TAB_A (F_A, F_B) VALUES ('${value4fa}', ${value4fb})"
  </code></pre>
  
  <p>Groovy informs me that I have introduced a security hole, because Groovy can not use PreparedStatement to execute the SQL query. </p>
  
  <p>Could anybody explain me how to force Groovy to evaluate query body correctly and prepare the variables?</p>