title: Postgis: function st_contains does not exist
body: <p>I am struggling to get a simple Postgresql/Postgis statement to work, I need all points within a polygon (in this case a rectangle)</p>
  
  <pre><code>SELECT * FROM points_table WHERE ST_Contains( ST_GEOMFROMTEXT('POLYGON((51.8121, 0.13712199999997665, 51.9078, 0.21444399999995767))'), points_table.geom)
  </code></pre>
  
  <p>The error reads </p>
  
  <pre><code>ERROR:  function st_contains(geometry, geography) does not exist
  LINE 1: SELECT * FROM points_table WHERE ST_Contains( ST_GEOMFRO...
                                               ^
  HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
  
  ********** Error **********
  
  ERROR: function st_contains(geometry, geography) does not exist
  SQL state: 42883
  Hint: No function matches the given name and argument types. You might need to add explicit type casts.
  Character: 38
  </code></pre>
  
  <p>The answer from <a href="https://stackoverflow.com/questions/46298611/how-to-find-all-points-within-polygon-in-postgis">this question</a> amongst others suggests my statement is correct.</p>