MySQL Join Query to Sum a Field in One Table based on Its Corresponding Login ID in another Table -
i have mysql table comment
following fields:
loginid submissionid points
i have mysql table called submission
following fields:
loginid submissionid
for given submissionid
, loginid
in 2 tables represent different things , therefore nor correspond.
i join sum points
loginid
. however, not loginid
in comment
, rather loginid in submission
. connection between 2 tables made via submissionid
i can't work. below have far. i'm trying desired sum each loginid pulled another, third table, l.loginid
represents.
how can this?
left join ( select c2.submissionid, c2.loginid sum(points) total comment c2 inner join submission s2 on s2.submissionid = c2.submissionid group c2.submissionid ) cscs on cscs.loginid = l.loginid
select s2.loginid, sum(points) total submission s2 inner join comment c2 on s2.submissionid = c2.submissionid group s2.loginid
this give points sum each loginid in submission table.
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