select sc.name, st.name ||' '|| st.last_name as Fullname
FROM schools as sc
  LEFT JOIN students as st ON sc.id = st.school_id;


select sc.name, st.name ||' '|| st.last_name as Fullname
FROM schools as sc
  RIGHT JOIN students as st ON sc.id = st.school_id;

select st.name ||' '|| st.last_name as Fullname, lec.name as Lecture, sg.student_grade
from student_grades as sg
  INNER JOIN students as st on sg.student_id = st.id
  INNER JOIN lectures as lec on sg.lecture_id = lec.id;


select st.name ||' '|| st.last_name as Fullname, lec.name as Lecture, sg.student_grade
from student_grades as sg
  FULL JOIN students as st on sg.student_id = st.id
  Full JOIN lectures as lec on sg.lecture_id = lec.id;

select sc.name, st.name ||' '|| st.last_name as Fullname, lec.name, lec.passing_grade, sg.student_grade
from student_grades as sg
  JOIN students as st on sg.student_id = st.id
  JOIN schools as sc on st.school_id = sc.id
  JOIN lectures as lec on sg.lecture_id = lec.id;

select st.name ||' '|| st.last_name as Fullname, lec.name, sg.student_grade
from student_grades as sg
  JOIN students as st on sg.student_id = st.id
  JOIN lectures as lec on sg.lecture_id = lec.id
where sg.student_grade >= lec.passing_grade;

SELECT st.name ||' '|| st.last_name as Fullname
from student_grades as sg
  join students as st on sg.student_id = st.id
  join lectures as lec ON sg.lecture_id = lec.id
where sg.student_grade > 60
GROUP BY st.name,st.last_name
Having count(sg.student_grade) = (select count(lc.passing_grade) from lectures lc)

select sg.student_grade, pg.passing_grade, st.name ||' '|| st.last_name as Fullname, pg.name
from student_grades as sg
  JOIN students as st on  sg.student_id = st.id
  JOIN lectures as pg on sg.lecture_id = pg.id
WHERE sg.student_grade >= pg.passing_grade;

select sg.student_grade, pg.passing_grade, st.name ||' '|| st.last_name as Fullname, pg.name, sc.id
from student_grades as sg
  JOIN students as st on  sg.student_id = st.id
  JOIN lectures as pg on sg.lecture_id = pg.id
  JOIN schools as sc on sc.id = st.school_id
WHERE sg.student_grade >= pg.passing_grade and sc.id = 1 or sc.id = 2 or sc.id = 6;

select sc.Fullname
from (SELECT st.name ||' '|| st.last_name as Fullname, sc.id
      from student_grades as sg
        join students as st on sg.student_id = st.id
        join lectures as lec ON sg.lecture_id = lec.id
        join schools as sc on st.school_id = sc.id
      where sg.student_grade > 60
      GROUP BY st.name,st.last_name,sc.id
      Having count(sg.student_grade) = (select count(lc.passing_grade) from lectures lc)) as sc
where sc.id = 1 or sc.id = 2select sg.student_grade, pg.passing_grade, st.name ||' '|| st.last_name as Fullname, pg.name, sc.id
from student_grades as sg
JOIN students as st on  sg.student_id = st.id
JOIN lectures as pg on sg.lecture_id = pg.id
JOIN schools as sc on sc.id = st.school_id
WHERE sg.student_grade >= pg.passing_grade and sc.id = 1 or sc.id = 2 or sc.id = 6; or sc.id = 6