Select a field having some content from a table

Question

Hi Friends,
I had a requiremen where I need to fetch the field(having some content).
I need to select FISTL field which is having some value (not space) from table BSIS into my internal table, so that I need to update this field value for all the line items with the same BELNR(doc number).
My Approach:
    SELECT SINGLE FISTL FROM BSIS INTO WA_FINAL-FISTL WHERE FISTL IS NOT NULL AND
                                                           BELNR = WA_BSIS-BELNR.           
But here if the first occurance of FISTL value in BSIS table in space, it is picking the spaces and updating my itab which means that a space value is not null.
Please suggest me how to put condition so that I can select FISTL field having some value in it.
Tried with read keyword also. But it is not accepting "IS INITIAL"  in where clause.
Please look into this.
Thanks,
Murali

Answer 1

Hello,
You should try
FISTL NE space
instead of IS NOT NULL.
As you might be aware ABAP data objects don't have 'NULL' values defined. You can use the 'NULL' values in Native SQL, but in case of Open SQL SAP says,
"When reading with the Open SQL statement SELECT, null values can be created by aggregate functions or an outer join, but they are converted to initial values of the correct type when passed to data objects."
Source: SAP documentation for NULL value.
BR,
Suhas