title: how to resolve function datediff(unknown, timestamp without time zone, timestamp without time zone) does not exist
body: <pre><code>SELECT "reviewedAt", "createdAt", DATEDIFF('hour', "createdAt"::timestamp, "reviewedAt"::timestamp) as hours_approved from "yadda$prod"."Application" 
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  <p>error [42883] ERROR: function datediff(unknown, timestamp without time zone, timestamp without time zone) does not exist Hint: No function matches the given name and argument types. You might need to add explicit type casts. Position: 36 </p>