COALESCE function in Select - Open SQL Enhancement ABAP on HANA - Part 7

 *&---------------------------------------------------------------------*

*& Report zr_opensql_11_coalesce_t

*&---------------------------------------------------------------------*

*&

*&---------------------------------------------------------------------*

REPORT zr_opensql_11_coalesce_t.

SELECT

 FROM vbak AS so

 LEFT OUTER JOIN vbfa AS flow

 ON flow~vbelv = so~vbeln

 AND flow~vbtyp_v = 'C'

 AND flow~vbtyp_n = 'M'

 LEFT OUTER JOIN vbrk AS inv

  ON inv~vbeln = flow~vbeln

  FIELDS so~vbeln AS sales_order,

         so~netwr AS so_amount,

         inv~netwr AS inv_amount,

         CASE WHEN inv~netwr IS NOT NULL  THEN  inv~netwr

         ELSE so~netwr

         END AS amount_net,

         COALESCE( inv~netwr , so~netwr ) as amount_co

  INTO TABLE @DATA(it_result).

IF sy-subrc IS INITIAL.

  cl_demo_output=>display( it_result ).

ENDIF.

*CASE WHEN arg1 IS NOT NULL THEN arg1

*     WHEN arg2 IS NOT NULL THEN arg2

*     ...

*     ELSE argn

*END

* COALESCE( arg1, arg2, ..., argn )

*A null value is an initial value of an empty column in the row of a database table.

*Null values do not correspond to any content of data objects in ABAP.

*In Open SQL, null values can handled using the condition IS NULL and the function coalesce.