diff --git a/src/main/java/com/samskivert/depot/impl/PostgreSQLBuilder.java b/src/main/java/com/samskivert/depot/impl/PostgreSQLBuilder.java
index 3e6ce94..e357b7d 100644
--- a/src/main/java/com/samskivert/depot/impl/PostgreSQLBuilder.java
+++ b/src/main/java/com/samskivert/depot/impl/PostgreSQLBuilder.java
@@ -87,8 +87,8 @@ public class PostgreSQLBuilder
 
         @Override public Void visit (DatePart exp)
         {
-            return appendFunctionCall(
-                "date_part", Exps.value(translateDatePart(exp.getPart())), exp.getArg());
+            String datePart = "'" + translateDatePart(exp.getPart()) + "'";
+            return appendFunctionCall("date_part", Exps.literal(datePart), exp.getArg());
         }
 
         @Override