SQL. How to use a loop?. Postgresql

Question

I have a request and I want to apply a cycle to it which will be held 11 times. How to do it ?

Insert into Mark (id_student,mark,date,id_discteacher)
Select student.id_student,'10','2019-05-09',id_discteacher from discipline_teacher 
JOIN discipline using(id_discipline)
join teacher using(id_teacher)
join group on class.id_group = discipline_teacher.group  
join student on student.group = group.id_group
where EXISTS (select * from discipline_teacher 
             join group on discipline_teacher.group = group.id_group
              join student on student.group = group.id_group
              JOIN discipline using(id_discipline)
              join teacher using(id_teacher)
              where discipline.title ='math' and teacher.id_teacher=1 and group.title ='2' and group.kurs ='А') 
              and discipline.title ='math' and teacher.id_teacher=1 and group.title ='2' and group.kurs ='А' and student.name = 'Anna' and student.last_name ='Makeeva';

What do you mean "apply a cycle to it which will be help 11 times? — Gordon Linoff
– Gordon Linoff, Commented May 19, 2019 at 15:58
@GordonLinoff I want the loop to work 11 times on this request. — JuniorLittle
– JuniorLittle, Commented May 19, 2019 at 16:02

Gordon Linoff · Accepted Answer · 2019-05-19 15:59:08Z

2

If you want to multiply the number of records by 11, then use generate_series():

with t as (<your query here>)
select t.*
from t cross join
     generate_series(1, 11, 1);

answered May 19, 2019 at 15:59

Gordon Linoff

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2 Comments

JuniorLittle Over a year ago

ERROR: WITH query "t" does not have a RETURNING clause LINE 20: from t cross join

Jeremy Over a year ago

Are you trying to put it in a function? Edit: I think I see. Just put the select part of your query in that part, to see if the result is what you expect.

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