How to select top one in CDS view ?

Question

I have tried following logic to select top one in CDS view but its giving error -
define view Cds_View_First_Reference as select  top one CReferredObject from CDSVIEWCROSSREF

Answer 1

Hi Ruchi,
since you posted this question in "ABAP in Eclipse" I assume you are asking about CDS in ABAP. This is important because the CDS features sets in ABAP and (native) HANA are different.
Be that as it may,, SELECT TOP 1 is neither supported in the CDS implementation in ABAP nor in HANA.
In ABAP you might consider using the min() or max() function together with the appropriate GROUP BY clause in the CDS view (depending on what you want to achieve), but you can also easily "implement" this in the Open SQL statement which selects from your CDS view.
Using the additions SELECT SINGLE or UP TO 1 ROWS and an appropriate ORDER BY clause in Open SQL, you can achieve the same as SELECT TOP 1.
Unfortunately there is currently no possibility to define a view which delivers the TOP 1 which you can again use in another view ("view on view").
Kind regards
Chris