declare @Sql varchar(1000)
declare @ACCOUNT varchar(50)='AA'  --@ACCOUNT 为 testName 时也需要符合
Set @Sql ='select * from T_ORDER where   (' +
            CASE @ACCOUNT WHEN '-1' THEN '1=1' 
            ELSE 'ACCOUNT = '''+ CAST(@ACCOUNT AS varchar(50)) + ''''
            END 
        + ') '
            
select @Sql;