MYSQL错误1064，如何解决它？

Question

我正在使用MySQL并出现sql错误。我需要有不同的列datetime和每一个不同的日期时间，我想表明的最大impact_id

选择MAX（impact_id），从新闻 不同datetim 其中impact_id不是null datetim不为空
按datetim 为了通过datetim ASC

我收到错误

SQL Error (1064): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'distinct datetim from news where impact_id is not null and 

datetim不为空”

CREATE TABLE `news` (
    `datetim` DATETIME NULL DEFAULT NULL, 
    `symbol` VARCHAR(50) NULL DEFAULT NULL, 
    `impact` VARCHAR(50) NULL DEFAULT NULL, 
    `_id` MEDIUMINT(9) NOT NULL AUTO_INCREMENT, 
    `impact_id` INT(11) NULL DEFAULT NULL, 
    PRIMARY KEY (`_id`) 
) 
COLLATE='utf8_general_ci' 
ENGINE=InnoDB 
AUTO_INCREMENT=3072 
; 

Answer 1

select distinct max(impact_id),datetim from news where impact_id is not null and datetim is not null group by datetim order by datetim asc