Parameter to be passed for Field to read in SAP connector: Read SAP table(preview)

I am not able to fetch multiple columns/fields from SAP table using Read SAP table(preview) action in Logic app. I tried passing it as array but it is throwing an error:

unexpected token StartArray. Path queries.fieldname.'.'

If we don't pass any parameter to fields to read, it is fetching all the rows.

Can you suggest me how can I fetch multiple field from Read SAP table(preview)?

It's not clear what the parameter should be to specify the fields. As an alternative you can use the '[RFC] Call function in SAP'-connector and call the RFC BBP_RFC_READ_TABLE.

In the 'Input RFC parameters' you can specify the fields to return.

<BBP_RFC_READ_TABLE xmlns="http://Microsoft.LobServices.Sap/2007/03">
    <QUERY_TABLE>LAGP</QUERY_TABLE>
    <OPTIONS>
        <RFC_DB_OPT>
            <TEXT>LGNUM = '800' AND LGTYP = '001'</TEXT>
        </RFC_DB_OPT>
    </OPTIONS>
    <DELIMITER>;</DELIMITER>
    <FIELDS>
        <RFC_DB_FLD>
            <FIELDNAME>LGTYP</FIELDNAME>
        </RFC_DB_FLD>
        <RFC_DB_FLD>
            <FIELDNAME>LGPLA</FIELDNAME>
        </RFC_DB_FLD>
    </FIELDS>
</BBP_RFC_READ_TABLE>