mysql - SQL command to show 0 if doesn't exist in the join table -


i'm having problem in sql command.

i have table questions, other possible answers questions , other replies users.

imagine following example:

question 1: win semi-final?
aswners: a) portugal b) spain
replies: 10 people voted b) spain, 0 people voted a) portugal

select a.answer, count(r.id) total replies r left join answers on a.id = r.id_answer left join questions q on q.id = a.id_question q.id = 1 group r.id_answer 

my point the
select result:
spain 10
portugal 0

but can't, don't know how it, because way did, result asnwers replies on replies table. this:
spain 10

you have start questions, , left join replies.

select a.answer, count(r.id_answer) total questions q join answers on ( a.id_question = q.id ) left join replies r on ( r.id_answer = a.id ) q.id = 1 group a.id, a.answer 

with current query don't need question:

select a.answer, count(r.id_answer) total answers left join replies r on ( r.id_answer = a.id ) a.id_question = 1 group a.id, a.answer 

see example second query on sql fiddle, returns:

answer      total spain       10 portugal    0 

Comments

Popular posts from this blog

c# - SVN Error : "svnadmin: E205000: Too many arguments" -

c# - Copy ObservableCollection to another ObservableCollection -

All overlapping substrings matching a java regex -