Hi Priyanka,
You would see a separate entity set in the metadata for you input variable. The properties of this entity should have the annotation sap: parameter= "mandatory” or sap: parameter= "optional”.
In the Service document there would be a href attribute mentioned for the corresponding QueryParameter Entity.
Your url should look like
http://<host>:<port>/sap/opu/odata/sap/<ServiceName>/<href attribute value>(Value In your case the value of ZDATE1)/Results
For more information, you can use the blog How to Create OData Services for Analytic Queries
Thanks & Regards,
Mohan