MongoDB how to $project aggregate with multiple $sum? - mongodb

Question

For MongoDB, need to group on event and supply multiple attribute fields.
My purpose is to show for a group the associated field attributes together with a list of sum totals from numeric fields.
For the MongoDB the aggregate has $group and $project. $project can show fields listed within the $group.
My $group is working fine by itself, e.g, without the $project. When I supply $project before or after the $group, I receive the following error:
query failed: (Location40323) A pipeline stage specification object must contain exactly one field.
My code is as follows:
db.collection.aggregate([
{
$project: {
eventName: "$EVENT_TYPE",
registeredDate: "$BEGIN_DATE_TIME",
stateName: "$STATE",
damageCosts: "$DAMAGE_PROPERTY",
peopleCosts: "$DEATHS_DIRECT",
injuriyCosts: "$INJURIES_DIRECT",
cropCosts: "$DAMAGE_CROPS"
},
$group: {
_id: "$EVENT_TYPE",
totalPropCost: {
$sum: "$DAMAGE_PROPERTY"
},
totalDeaths: {
$sum: "$DEATHS_DIRECTY"
},
totalInjury: {
$sum: "$INJURIES_DIRECT"
},
totalCropCost: {
$sum: "$DAMAGE_CROPS"
}
}
}
])
Alternately: attempted to use the $push command, and it looks like a valid run with $push:
db.collection.aggregate([
{
$group: {
_id: "$EVENT_TYPE",
totalPropCost: {
$sum: "$DAMAGE_PROPERTY"
},
totalDeaths: {
$sum: "$DEATHS_DIRECTY"
},
totalInjury: {
$sum: "$INJURIES_DIRECT"
},
totalCropCost: {
$sum: "$DAMAGE_CROPS"
},
events: {
$push: {
name: "$EVENT_TYPE",
date: "$BEGIN_DATE_TIME",
state: "$STATE"
}
}
}
}
])
I use the following sample of data for this mongoDb query, which without the $project, works correct on $sum.
[
{
"BEGIN_YEARMONTH": 201007,
"BEGIN_DAY": 7,
"END_YEARMONTH": 201007,
"END_DAY": 7,
"END_TIME": 1630,
"STATE": "NEW HAMPSHIRE",
"YEAR": 2010,
"EVENT_TYPE": "Heat",
"BEGIN_DATE_TIME": "07-JUL-10 12:51:00",
"END_DATE_TIME": "07-JUL-10 16:30:00",
"INJURIES_DIRECT": 0,
"DEATHS_DIRECT": 0,
"DAMAGE_PROPERTY": "0.00K",
"DAMAGE_CROPS": "0.00K"
},
{
"BEGIN_YEARMONTH": 201001,
"BEGIN_DAY": 17,
"END_YEARMONTH": 201001,
"END_DAY": 18,
"END_TIME": 1500,
"STATE": "NEW HAMPSHIRE",
"YEAR": 2010,
"MONTH_NAME": "January",
"EVENT_TYPE": "Heavy Snow",
"BEGIN_DATE_TIME": "17-JAN-10 23:00:00",
"END_DATE_TIME": "18-JAN-10 15:00:00",
"INJURIES_DIRECT": 0,
"DEATHS_DIRECT": 0,
"DAMAGE_PROPERTY": "0.00K",
"DAMAGE_CROPS": "0.00K"
}
]

Answer 1

For this investigation, after many tries, and other ideas welcome, especially using alternative solutions with $project. By and by, this much is giving me adequate results. The $push command appear to work best. If anyone knows how to get a $project working, please advise and provide explanation. For now, $push work on one solutions for group and list of attribute fields.
db.collection.aggregate([
{
$group: {
_id: "$STATE",
totalPropCost: {
$sum: "$DAMAGE_PROPERTY"
},
totalDeaths: {
$sum: "$DEATHS_DIRECTY"
},
totalInjury: {
$sum: "$INJURIES_DIRECT"
},
totalCropCost: {
$sum: "$DAMAGE_CROPS"
},
events: {
$push: {
eventName: "$EVENT_TYPE",
CzName: "$CZ_NAME",
cZTimeZone: "$CZ_TIMEZONE",
eventDate: "$BEGIN_DATE_TIME",
eventMonth: "$MONTH_NAME",
state: "$STATE",
observer: "$SOURCE"
}
}
}
}
])