Using IN operator with a variable in SAP HANA

I am trying to use a variable as input for a WHERE condition having an IN clause using SAP HANA.

For example:

DO
BEGIN
    DECLARE a VARCHAR(100) = '1000,1001';
    DECLARE b NVARCHAR(100) ARRAY = ARRAY('1000','1001');
    DECLARE c TABLE (valuelist NVARCHAR(100));
    --SELECT '1001' INTO valuelist FROM :c;
    --:c.INSERT('1001','1000');
    DECLARE e NVARCHAR(100) = ' ''1000'',''1001'' ';
    DECLARE f NVARCHAR(100) = '"STATIONID" IN (''1000'',''1001'')';

select
    STATIONID
    
    from MY_TABLE
    
    where STATIONID IN ('1000','1001') -- working fine, but want to use a variable here
    -- where STATIONID IN (:a)
    -- where STATIONID IN (:b)
    -- where STATIONID IN :c
    -- where :f
    
    order by STATIONID;
END

However, all my attempts, you can see some of them above, do fail when having multiple values in my condition. STATIONID really is a string field.

Any hints on how to do this?

Answer

Finally I figured out how I can use a variable array together with a variable table by using UNNEST. This is working just fine:

DO
BEGIN
    DECLARE STATION_TMP_ARRAY NVARCHAR(10) ARRAY = ARRAY('1000','1001','1002','1003','1004');
    DECLARE STATION_TMP_TABLE TABLE ("tmp_stationid" NVARCHAR(10)) = UNNEST(:STATION_TMP_ARRAY) AS ("tmp_stationid");
    
select
    STATIONID
    
    from MY_TABLE
    
    where "STATIONID" IN (SELECT "tmp_stationid" FROM :STATION_TMP_TABLE)
    
    order by STATIONID;
END