sql - Single query to count by category by joining multiple tables -

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i have following 3 tables. write single query count of number of courses enrolled in student every difficulty level, , total number of courses enrolled in well. students have not enrolled should listed too.

students table: student id      student name 1               alice 2               bob 3               charlie 4               david  courses table: course id       course name             difficulty level 1               arithmetic              1 2               advanced calculus       3 3               algebra                 2 4               trignometry             2  enrollment table: enrollment id   student id      course id 1               1               1 2               1               3 3               1               4 4               2               2 5               2               3 6               2               4 7               3               3

here's expected output:

output: student id      student name    total courses       courses        courses        courses                                 enrolled in         difficulty level 1  difficulty level 2  difficulty level 3 1               alice           3                   1                   2                   0 2               bob             3                   0                   2                   1 3               charlie         1                   0                   1                   0 4               david           0                   0                   0                   0

i appreciate this. i've tried few different queries , finding hard arrive @ single query lists students.

select  s.[student id] ,       s.[student name] ,       count(c.[course id]) ,       count(case when c.[difficulty level] = 1 end) ,       count(case when c.[difficulty level] = 2 end) ,       count(case when c.[difficulty level] = 3 end)    students s left join             enrollment e on      e.[student id] = s.[student id] left join             courses c on      c.[course id] = e.[course id] group         s.[student id] ,       s.[student name]

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