Mendapatkan peringkat baris dalam kueri mysql

Kesalahannya cukup jelas. Setiap tabel turunan harus memiliki aliasnya sendiri. Anda perlu alias (SELECT @rownum := 0) seperti ini:

SELECT 
  @rownum := @rownum + 1 AS rank, 
  name,
  vote 
FROM table, (SELECT @rownum := 0) t --This what you were missing an alias
ORDER BY vote DESC

Demo Fiddle SQL