result = db.student.find({},
   { "fname": 1, "lname":1, "_id": 0 }  
).toArray()

// May not always work as toArray() returns a promise,
// which may not be ready for use.
result.forEach((x,i) => console.log('student #' + String(i) + ': ' + x["fname"] + ' ' + x["lname"]))


// Show the names and credits (ach) of students majoring in 'CSCI' and having 40 or more credits.
db.student.find(
   { "major": "CSCI", "ach" : {$gte: 40} },
   { "fname": 1, "lname":1, "major": 1, "ach":1, "_id": 0 }  
)

// Show the first name and last name of students with a first name starting with a L or B, case insensitive.
db.student.find(
   { "fname": { $regex: /^[lb]/, $options: "i" } },
   { "fname": 1, "lname":1, "_id": 0 }  
)

// Show the names and credits (ach) of students majoring in 'CSCI' and having 40 or more credits.
db.student.find(
   { "$and": [ { "major": "CSCI"}, { "ach": {"$gte": 40}} ] },
   
   // query: vs. SQL: WHERE major = 'CSCI' AND ach >= 40
   { "fname": 1, "lname":1, "ach":1, "_id": 0 }  
)

// a sequence of steps defined by the list [], first argument.
db.faculty.aggregate([
    {"$group" : {_id:"$deptCode", "count":{$sum:1}}}
])

db.faculty.aggregate([
    {"$group" : {_id:"deptCode", "count":{$sum:1}}}
])

// pipeline: step i's output become step (i+1)'s input
db.faculty.aggregate(
   [  
      { $group: { "_id": "$deptCode", "count": {$sum:1}} },
      { $project: { "deptCode": "$_id" , "num_faculty": "$count",  "_id": 0}}
   ]
)

db.enroll.find(
	{"grade": "B+"},
	{"_id": 0, "classId": 1, "stuId":1, "grade":1}
)