MYSQL中TIMESTAMPDIFF和时间戳字段直接相减的区别 |
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MYSQL中TIMESTAMPDIFF和时间戳字段直接相减的区别
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使用TIMESTAMPDIFF函数与直接使用两个字段进行作差的区别
比如用 e n d _ t i m e − s t a r t _ t i m e end\_time - start\_time end_time−start_time，那么两个时间戳的时间差的进制会是按照100的。比如相差1分钟，但查询出来的是却是100。 但是用 T I M E S T A M P D I F F ( s e c o n d , s t a r t _ t i m e , e n d _ t i m e ) TIMESTAMPDIFF(second, start\_time, end\_time) TIMESTAMPDIFF(second,start_time,end_time)的话，两个时间戳相差超过1分钟的话，就会是60。 实验的SQL语句： DROP TABLE IF EXISTS tb_user_video_log, tb_video_info; CREATE TABLE tb_user_video_log ( id INT PRIMARY KEY AUTO_INCREMENT COMMENT '自增ID', uid INT NOT NULL COMMENT '用户ID', video_id INT NOT NULL COMMENT '视频ID', start_time datetime COMMENT '开始观看时间', end_time datetime COMMENT '结束观看时间', if_follow TINYINT COMMENT '是否关注', if_like TINYINT COMMENT '是否点赞', if_retweet TINYINT COMMENT '是否转发', comment_id INT COMMENT '评论ID' ) CHARACTER SET utf8 COLLATE utf8_bin; CREATE TABLE tb_video_info ( id INT PRIMARY KEY AUTO_INCREMENT COMMENT '自增ID', video_id INT UNIQUE NOT NULL COMMENT '视频ID', author INT NOT NULL COMMENT '创作者ID', tag VARCHAR(16) NOT NULL COMMENT '类别标签', duration INT NOT NULL COMMENT '视频时长(秒数)', release_time datetime NOT NULL COMMENT '发布时间' )CHARACTER SET utf8 COLLATE utf8_bin; INSERT INTO tb_user_video_log(uid, video_id, start_time, end_time, if_follow, if_like, if_retweet, comment_id) VALUES (101, 2001, '2021-10-01 10:00:00', '2021-10-01 10:00:30', 0, 1, 1, null), (102, 2001, '2021-10-01 10:00:00', '2021-10-01 10:00:21', 0, 0, 1, null), (103, 2001, '2021-10-01 11:00:50', '2021-10-01 11:01:25', 0, 1, 0, 1732526), (102, 2002, '2021-10-01 11:00:00', '2021-10-01 11:00:30', 1, 0, 1, null), (103, 2002, '2021-10-01 10:59:05', '2021-10-01 11:00:05', 1, 0, 1, null), (101, 2003, '2020-09-01 10:00:00', '2020-09-01 10:00:42', 1, 0, 1, null), (102, 2003, '2021-09-01 10:00:00', '2021-09-01 10:01:06', 1, 0, 1, null); INSERT INTO tb_video_info(video_id, author, tag, duration, release_time) VALUES (2001, 901, '影视', 30, '2021-01-01 7:00:00'), (2002, 901, '美食', 60, '2021-01-01 7:00:00'), (2003, 902, '旅游', 90, '2020-01-01 7:00:00');得到的数据是
然后查询对比 SELECT TIMESTAMPDIFF(second,tvl.start_time,tvl.end_time) as tsd ,tvl.end_time - tvl.start_time as tt from tb_user_video_log tvl得到结果
就是 2021-09-01 10:01:06与2021-09-01 10:00:00用 e n d _ t i m e − s t a r t _ t i m e end\_time - start\_time end_time−start_time得到的结果是106，但是用 T I M E S T A M P D I F F ( s e c o n d , s t a r t _ t i m e , e n d _ t i m e ) TIMESTAMPDIFF(second, start\_time, end\_time) TIMESTAMPDIFF(second,start_time,end_time)得到的结果是66。2021-09-01 10:59:05与2021-09-01 11:00:05用 e n d _ t i m e − s t a r t _ t i m e end\_time - start\_time end_time−start_time得到的结果是4100（相当于11:00:05-10:59:05是用100进制去减掉，因此相当于分钟数00减59的时候，要向11借一个1，换算成100*100 - 59 * 100 = 4100），但是用 T I M E S T A M P D I F F ( s e c o n d , s t a r t _ t i m e , e n d _ t i m e ) TIMESTAMPDIFF(second, start\_time, end\_time) TIMESTAMPDIFF(second,start_time,end_time)得到的结果是60。 |
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