表结果:
create table user( id int , username varchar(10), create_time datetime, type int ) insert into user (`id`,`username`,`create_time`,`type`) values ('1','张三','2019-04-25 14:36:41','1'), ('1','张三','2019-04-25 14:37:10','2'), ('1','张三','2019-04-25 14:37:26','1'), ('1','张三','2019-04-27 14:38:08','1'), ('1','张三','2019-04-26 14:36:02','1'), ('1','张三','2019-04-26 14:36:19','2'), ('1','李四','2019-04-25 14:39:50','1'), ('1','李四','2019-04-26 14:39:49','1'), ('1','李四','2019-04-26 14:39:48','1'), ('1','李四','2019-04-27 14:39:48','1'), ('1','李四','2019-04-27 14:39:44','1'), ('1','王五','2019-04-25 14:36:41','1');
数据表:
静态用 case when then
mysql 只能,动态用存储 ,
SQL Server中行列转换用 Pivot UnPivot
结果:
sql:
SET @str=''; set @sql_temp=''; SELECT @str:=CONCAT(@str,'sum(IF(left(create_time,10)='',create_time,''',',1,0)',') AS ' ,'''',create_time,'''',',') as aa into @sql_temp FROM ( SELECT left(create_time,10) as create_time FROM `user` group by left(create_time,10)) A order by length(aa) desc limit 1; SET @result_sql=CONCAT('SELECT user.username, ',LEFT(@sql_temp,char_length(@sql_temp)-1),' FROM user GROUP BY username' ); PREPARE stmt FROM @result_sql; EXECUTE stmt ; deallocate prepare stmt