#900 - Error - Can't fetch JsonDB field - org.postgresql.util.PSQLException: ERROR: could not identify an equality operator for type json

src/main/java/io/ebeaninternal/server/query/SqlTreeNodeExtraJoin.java

@@ -56,6 +56,11 @@ class SqlTreeNodeExtraJoin implements SqlTreeNode {
     // nothing to do here
   }
 
+  @Override
+  public void appendDistinctOn(DbSqlContext ctx, boolean subQuery) {
+    // do nothing here ...
+  }
+
   @Override
   public boolean isAggregation() {
     return false;