MySQL 8.0

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select @@version;


@@version


8.0.30


CREATE TABLE registros(
  id int primary key auto_increment,
  fecha DATETIME
);
INSERT INTO registros(fecha)
values
("2018-10-26 06:00:00"),
("2018-10-26 06:00:00"),
("2018-10-26 08:00:00"),
("2018-10-26 08:00:00"),
("2018-10-26 08:00:00"),
("2018-10-26 08:00:00"),
("2018-10-26 12:00:00"),
("2018-10-26 12:00:00");

Records: 8  Duplicates: 0  Warnings: 0


select * from registros;


id
fecha


1
2018-10-26 06:00:00

2
2018-10-26 06:00:00

3
2018-10-26 08:00:00

4
2018-10-26 08:00:00

5
2018-10-26 08:00:00

6
2018-10-26 08:00:00

7
2018-10-26 12:00:00

8
2018-10-26 12:00:00


SELECT count(id) as total, DATE_FORMAT(fecha,'%H:%i:%s') AS "#Registro"
from registros
group by fecha;


total
#Registro


2
06:00:00

4
08:00:00

2
12:00:00

id	fecha
1	2018-10-26 06:00:00
2	2018-10-26 06:00:00
3	2018-10-26 08:00:00
4	2018-10-26 08:00:00
5	2018-10-26 08:00:00
6	2018-10-26 08:00:00
7	2018-10-26 12:00:00
8	2018-10-26 12:00:00