0 - 2 of 2 tags for embedded dynamic sql

When i execute the below code in a STORED PROCEDURE i get an syntax error saying "Expects somthing like an EXCEPT keyword UNION keyword or MINUS keyword between a between a String and YYYYMMDD". Please help me fix this syntax error. Thanks.
Replace Procedure Sample_Proc(

I am trying to randomly segment a table into groups where the number of groups can change, as well as the sample percentage of each group.   The number of samples and the distribution is coming from an Excel spreadsheet.