Use of dynamic table names in mysql stored procedures

Explain (500); setv_sqlconcat (& #39; selectWXPayBillID, WXPayMoneyFROM & #39;, tablename); selectv_ SQL; set @ v_sqlv_ SQL; is there a problem with the code written here? Preparestmtfrom @ v_ SQL; EXECUTEstmt; deallocatepreparestmt; e mysql stored procedure

BEGIN

If tablename is not null thendeclare v_ SQL varchar (500); set v_ SQL = concat ('select WXPayBillID, WXPayMoney FROM ', tablename); select v_ SQL; set @ v_ SQL = v_ SQL; /// is there a problem? Prepare stmt from @ v_ SQL; EXECUTE stmt; deallocate prepare stmt; end if;

END
Why do I always prompt illegal symbol: '@'; where did I write an error in this stored procedure.