MYSQL SELECT 多行合二为一

Question

Ok, this is complicated for me to get out there, but here we go.

I have a family/person attendance table containing the following fields:

| mail_no (FamilyID) | meid (Person ID) | date | status (A/P)|

On the family attendance screen, I need to pull the data and group it in the following format:

meid	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
123	1	0	0	1	0	0	0	0	0	0	0	1
124	2	3	2	0	0	0	0	1	1	2	2	1

Currently, my PHP looks like this:

$year = "2020";
$where_clause = "AND ATDATA.mail_no='".$myrow['mail_no']."' AND ATDATA.status='A'";

SELECT meid,
    (SELECT COUNT(*) FROM ATDATA WHERE LEFT(ATDATA.date,7)= '".$year."-01' ".$where_clause.") as month1,
    (SELECT COUNT(*) FROM ATDATA WHERE LEFT(ATDATA.date,7)= '".$year."-02' ".$where_clause.") as month2,
    (SELECT COUNT(*) FROM ATDATA WHERE LEFT(ATDATA.date,7)= '".$year."-03' ".$where_clause.") as month3,
    (SELECT COUNT(*) FROM ATDATA WHERE LEFT(ATDATA.date,7)= '".$year."-04' ".$where_clause.") as month4,
    (SELECT COUNT(*) FROM ATDATA WHERE LEFT(ATDATA.date,7)= '".$year."-05' ".$where_clause.") as month5,
    (SELECT COUNT(*) FROM ATDATA WHERE LEFT(ATDATA.date,7)= '".$year."-06' ".$where_clause.") as month6,
    (SELECT COUNT(*) FROM ATDATA WHERE LEFT(ATDATA.date,7)= '".$year."-07' ".$where_clause.") as month7,
    (SELECT COUNT(*) FROM ATDATA WHERE LEFT(ATDATA.date,7)= '".$year."-08' ".$where_clause.") as month8,
    (SELECT COUNT(*) FROM ATDATA WHERE LEFT(ATDATA.date,7)= '".$year."-09' ".$where_clause.") as month9,
    (SELECT COUNT(*) FROM ATDATA WHERE LEFT(ATDATA.date,7)= '".$year."-10' ".$where_clause.") as month10,
    (SELECT COUNT(*) FROM ATDATA WHERE LEFT(ATDATA.date,7)= '".$year."-11' ".$where_clause.") as month11,
    (SELECT COUNT(*) FROM ATDATA WHERE LEFT(ATDATA.date,7)= '".$year."-12' ".$where_clause.") as month12
  FROM ATDATA 
  WHERE ATDATA.mail_no='".$myrow['mail_no']."' AND ATDATA.status='A'
  GROUP BY meid,month1, month2, month3, month4"

I'm getting the following output, which has the meid's split per row, but the underlying data is grouped on mail_no. How can I get the data grouped by meid instead?

meid	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
1752	5	7	3	0	0	0	0	0	0	0	0	6
198	5	7	3	0	0	0	0	0	0	0	0	6
199	5	7	3	0	0	0	0	0	0	0	0	6

Answer 1

hmmm hey

Just group by 'meid', remove the months in the group by... Then do counts where month = Jan... month = Feb... in your select...