Fix blank value issue in SP/RI columns (#549)

Author: sumitagarwalHcst

cid/builtin/core/data/queries/cid/summary_view.sql

@@ -22,8 +22,8 @@
  ,CASE
  -- WHEN ("savings_plan_savings_plan_a_r_n" <> '') THEN "savings_plan_savings_plan_a_r_n"
  -- WHEN ("reservation_reservation_a_r_n" <> '') THEN "reservation_reservation_a_r_n"
-  WHEN ("line_item_line_item_type" = 'Usage') THEN ''
-  ELSE '' END "ri_sp_arn"
+  WHEN ("line_item_line_item_type" = 'Usage') THEN CAST('' AS varchar)
+  ELSE CAST('' AS varchar) END "ri_sp_arn"
  , "line_item_product_code" "product_code"
  , "product_product_name" "product_name"
  , CASE

cid/builtin/core/data/queries/cid/summary_view_ri.sql

@@ -20,7 +20,7 @@
      ELSE 'OnDemand' END "purchase_option"
  , CASE
  -- WHEN ("savings_plan_savings_plan_a_r_n" <> '') THEN "savings_plan_savings_plan_a_r_n"
-     WHEN ("reservation_reservation_a_r_n" <> '') THEN "reservation_reservation_a_r_n" ELSE '' END "ri_sp_arn"
+     WHEN ("reservation_reservation_a_r_n" <> '') THEN "reservation_reservation_a_r_n" ELSE CAST('' AS varchar) END "ri_sp_arn"
  , "line_item_product_code" "product_code"
  , "product_product_name" "product_name"
  , CASE

cid/builtin/core/data/queries/cid/summary_view_sp.sql

@@ -21,7 +21,7 @@
  , CASE
      WHEN ("savings_plan_savings_plan_a_r_n" <> '') THEN "savings_plan_savings_plan_a_r_n"
      -- WHEN ("reservation_reservation_a_r_n" <> '') THEN "reservation_reservation_a_r_n"
-     ELSE '' END "ri_sp_arn"
+     ELSE CAST('' AS varchar) END "ri_sp_arn"
  , "line_item_product_code" "product_code"
  , "product_product_name" "product_name"
  , CASE

cid/builtin/core/data/queries/cid/summary_view_sp_ri.sql

@@ -20,7 +20,7 @@
       ELSE 'OnDemand' END "purchase_option"
   , CASE
       WHEN ("savings_plan_savings_plan_a_r_n" <> '') THEN "savings_plan_savings_plan_a_r_n"
-      WHEN ("reservation_reservation_a_r_n" <> '') THEN "reservation_reservation_a_r_n" ELSE '' END "ri_sp_arn"
+      WHEN ("reservation_reservation_a_r_n" <> '') THEN "reservation_reservation_a_r_n" ELSE CAST('' AS varchar) END "ri_sp_arn"
   , "line_item_product_code" "product_code"
   , "product_product_name" "product_name"
   , CASE