How to write the URL when odata with an InputParams type decimal

Dear friends,

        I create an calculation view with a input parameter(I_AMOUNT) which type decimal(2,2), I have the odata like this :

service namespace "TEST_M1"

{"XXXXXXX.TEST_TOOL::CAL_TEST_M1" as "TEST_M1" key generate local "GenID" aggregates always

  parameters via entity "InputParams";}

        And my URL like this :

s6hanaxs.hanatrial.ondemand.com/XXXXXX/TEST_TOOL/service/odata_caloddm1.xsodata/InputParams(I_AMOUNT='3.8')/Results?

but it have this error:

<messagexml:lang="en-US">Illegal query syntax.</message>

   So how do I write this URL with a decimal parameter ?

        Thank you so much for your help.

Best Regards

Zhang!