Syntax for COALESCE

Dear All,

I'm getting an error while using the COALESCE in SAP HANA Studio.  Here i will attach my query for concatenating Warehouse Code from Warehouse Master.

WHSList varchar(5000);

SELECT COALESCE(:WHSList || ',', '') || '[' || "WhsCode" || ']' INTO WHSList FROM OWHS;

Please Help on this