Anyone know how to convert decimal to timestamp on hana studio?

hi all,

I tried to create a calculated attribute to convert a decimal type record to timestamp.

here is what the original data looks like:　 20,130,302,230,000

in the calculated column dialog box,  I select TIMESTAMP as data type.

in the expression editor , i used this method :  longdate(ltrim(string("TST_TO"),'.'),'YYYYMMDD"T"HH24MISS')

You can refer to my screenshot. However , it didn't work. when I tried to have a data preview ,  it gave out an error message,

" Could not execute 'select * from "_SYS_BIC"."dtrc/AT_IC_RCMDED_DEL_DATE"' in 205 ms 408 µs .

[303]: invalid DATE, TIME or TIMESTAMP value: search table error:  [6931] attribute value is not a date or wrong syntax "

I searched google about the timestamp definition , longdate, sql script manual , and tried many ways like thousand times,  still can't figure out

what's wrong with the conversion.

after get the timestamp, i'd like to use localtoutc functions to convert it to UTC time.

Can anyone help ?

PS. my hana db is revision 61.

Thanks

Amon