MySQL 8.0

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create table userMessage (
 id int NOT NULL AUTO_INCREMENT, 
 userID int, 
 `text` varchar(30), 
 `date` timestamp,
 PRIMARY KEY(ID)
);
insert into userMessage (userID, `text`, `date`) values
(1,'text1', Now() - interval 1 day),
(1,'text2', Now() - interval 1 day),
(1,'text3', Now() - interval 2 day),
(2,'text4', Now() - interval 2 day),
(3,'text5', Now() - interval 2 day);
SELECT 
CAST(`date` AS DATE) AS MessageDate, 
COUNT(*) AS TotalMessages, 
COUNT(DISTINCT userID) AS TotalUniqueUsers
FROM userMessage
GROUP BY MessageDate
ORDER BY MessageDate DESC


MessageDate
TotalMessages
TotalUniqueUsers


2020-08-03
2
1

2020-08-02
3
3