Procedure With Calculation Engine (CE)

Hi,

I am new to HANA , I am trying  to learn it , please help me ,

How we can check   database error traces for additional details ?

SQL Script:-

CREATE PROCEDURE _SYS_BIC.get_pi_quantity_ce (

IN InvoicingStatus NVARCHAR(1),

OUT pi_quantity tt_pi_quantity )

          LANGUAGE SQLSCRIPT

          SQL SECURITY INVOKER

          READS SQL DATA AS  

BEGIN

/*****************************

          Write your procedure logic

*****************************/

lt_po =  

  CE_COLUMN_TABLE("SAP_HANA_EPM_DEMO"."sap.hana.democontent.epm.data::purchaseOrder",

             ["PurchaseOrderId", "CreatedAt", "PartnerId","InvoicingStatus"]);

lt_po_proj = CE_PROJECTION (:lt_po,

           ["PurchaseOrderId", "CreatedAt", "PartnerId" , "InvoicingStatus" ],

              '"InvoicingStatus" = :InvoicingStatus' );

lt_pi =

  CE_COLUMN_TABLE("SAP_HANA_EPM_DEMO"."sap.hana.democontent.epm.data::purchaseOrderItem",

                 ["PurchaseOrderItem", "Currency", "GrossAmount","ProductId","Quantity","QuantityUnit"]);

   pi_quantity = CE_JOIN(:lt_po_proj, :lt_pi, [ " PurchaseOrderId "  ],

                 ["PurchaseOrderId", "CreatedAt", "PartnerId", "InvoicingStatus",

                  "PurchaseOrderItem" , "Currency", "GrossAmount" , "ProductId" , "Quantity" , "QuantityUnit"]);                 

END;

Local table types .........

create type tt_pi_quantity as table (

PurchaseOrderId NVARCHAR(10),

CreatedAt DATE ,

PartnerId NVARCHAR(10),

InvoicingStatus Nvarchar(1),

PurchaseOrderItem NVARCHAR(10),

Currency nVARCHAR(5),

GrossAmount DECIMAL(15,2),

ProductId NvARCHAR(10),

Quantity DECIMAL(13,3),

QuantityUnit NvARCHAR(3)

)

I am getting following error ......................

I have checked each every line , but I have no clue why I am getting that error

ERROR      workshop/sessiona/00/procedures/get_pi_quantity_ce.procedure

           Repository: Internal error during statement execution, please see the database error traces for additional details;error executing statement; Join attribute must be available in projection list:  PurchaseOrderId : line 19 col 49 (at pos 1024) at ptime/query/checker/proc_check_cefunc.cc:410

ERROR      workshop/sessiona/00/procedures/get_pi_quantity_ce.procedure

           Repository: Encountered an error in repository runtime extension;object was not activated due to previous activation errors

ERROR      workshop/sessiona/00/procedures/get_pi_quantity_ce.procedure

           Object potentially broken due to transaction rollback.

ERROR                 exception 40177:

repository/base/activation/activator.cpp:828

Object potentially broken due to transaction rollback.