title: Convert string to array of arrays in PostgreSQL
body: <p>Want to 'simply' select the following <code>string</code> row (note that 'it is already' an array of arrays) to one of type <code>float[][]</code></p>
  <p><strong>From:</strong></p>
  <p><code>'[[1.1, 1], [2.2, 2]]'</code></p>
  <p><strong>To:</strong></p>
  <p><code>[[1.1, 1], [2.2, 2]]</code></p>
  <p>Any advice? Thanks!</p>