google spreadsheet query not working

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C#

Hello,

i ma trying to write code for getting particular row from google spreadsheet using SpreadsheetQuery like below :

AtomLink listFeedLink = worksheet.Links.FindService(GDataSpreadsheetsNameTable.ListRel, null);        
ListQuery listQuery = new ListQuery(listFeedLink.HRef.ToString());          
listQuery.SpreadsheetQuery = "First_Name=Sai";         
ListFeed listFeed = service.Query(listQuery);

but i am gettng error like this:
Google.GData.Client.GDataRequestException was unhandled by user code
Message=Execution of request failed: https://spreadsheets.google.com/feeds/list/......../private/full?sq=First_Name=Sai

Please help me to find solution

thanks in advance