mysql - How to check input value in a SQL query using CASE-WHEN -

i want create query insert data, 1 of field's data selected table based on value of input field.

i got fields : receiver,receiver_type etc. receiver value id 1 of 2 tables users or admins.

i created query like:

insert nots (receiver,receiver_type,...)     values (      case @receiver_type     when 1 (select id admins username=@param)     when 2 (select id users username=@param)     end  ,      1, ...) 

does sql offer input value checking, , if yes how write query?