MySQL按日期和计数分组

Question

I have table as below :-

With help of MySql query, I want result as below:

date        total    read    unread
2018-01-31   8        4        4
2018-02-01   2        2        0

Answer 1

Try this:

SELECT date, COUNT(*) as total,
SUM(CASE WHEN read = 1 THEN 1 ELSE 0) as read
SUM(CASE WHEN read = 0 THEN 1 ELSE 0) as unread
FROM yourtable
GROUP BY date

Answer 2

you can use case for aggregate the filtered value for read

select date
, count(*), sum(case when  read=1 then 1 else 0 end )  as read
, sum(case when  read=0 then 1 else 0 end )  as unread
from my_table 
group by date 

Answer 3

Try This we don't need case in the read column as 1 means read so we simply sum the value. It will help in the performance if we are dealing with the huge data:

SELECT date, 
    COUNT(*) as total,
    SUM(read) as read --Case not needed here
    SUM(CASE WHEN read = 0 THEN 1 ELSE 0) as unread
FROM yourtable
GROUP BY date

Answer 4

You have to group rows by date using group by , then you can use count to count the total number of rows within each date group (= total column). In order to obtain the number of read and unread, you can sum read and unread value

        SELECT date
             , COUNT(*) AS total
             , SUM(READ) AS READ
             , SUM(CASE WHEN READ = 0 THEN 1 ELSE 0 END) AS unread
        FROM mytable
        GROUP BY date