$trunc
The $trunc operator truncates a number to a specified decimal place.
$trunc
The $trunc operator truncates a number to a specified decimal place.
Parameters
| Parameter | Description |
|---|---|
<number> | The number to truncate. |
<decimal place> | The decimal place to truncate the specified number to. A positive value truncates to the right of the decimal point, and a negative value truncates to the left of the decimal point. |
Examples
Consider this sample document from the stores collection.
{
"_id": "0fcc0bf0-ed18-4ab8-b558-9848e18058f4",
"name": "First Up Consultants | Beverage Shop - Satterfieldmouth",
"location": {
"lat": -89.2384,
"lon": -46.4012
},
"staff": {
"totalStaff": {
"fullTime": 8,
"partTime": 20
}
},
"sales": {
"totalSales": 75670,
"salesByCategory": [
{
"categoryName": "Wine Accessories",
"totalSales": 34440
},
{
"categoryName": "Bitters",
"totalSales": 39496
},
{
"categoryName": "Rum",
"totalSales": 1734
}
]
},
"promotionEvents": [
{
"eventName": "Unbeatable Bargain Bash",
"promotionalDates": {
"startDate": {
"Year": 2024,
"Month": 6,
"Day": 23
},
"endDate": {
"Year": 2024,
"Month": 7,
"Day": 2
}
},
"discounts": [
{
"categoryName": "Whiskey",
"discountPercentage": 7
},
{
"categoryName": "Bitters",
"discountPercentage": 15
},
{
"categoryName": "Brandy",
"discountPercentage": 8
},
{
"categoryName": "Sports Drinks",
"discountPercentage": 22
},
{
"categoryName": "Vodka",
"discountPercentage": 19
}
]
},
{
"eventName": "Steal of a Deal Days",
"promotionalDates": {
"startDate": {
"Year": 2024,
"Month": 9,
"Day": 21
},
"endDate": {
"Year": 2024,
"Month": 9,
"Day": 29
}
},
"discounts": [
{
"categoryName": "Organic Wine",
"discountPercentage": 19
},
{
"categoryName": "White Wine",
"discountPercentage": 20
},
{
"categoryName": "Sparkling Wine",
"discountPercentage": 19
},
{
"categoryName": "Whiskey",
"discountPercentage": 17
},
{
"categoryName": "Vodka",
"discountPercentage": 23
}
]
}
]
}Example 1 - Fetch truncated location coordinates
To retrieve the truncated coordinates of stores within the "First Up Consultants" company, first run a query to filter stores by the company name. Then, use the $trunc operator on the latitude and longitude fields to return the desired result.
db.stores.aggregate([
{
$project: {
truncatedLat: { $trunc: ["$location.lat", 2] }
}
}
])The first three results returned by this query are:
[
{
"_id": "39acb3aa-f350-41cb-9279-9e34c004415a",
"name": "First Up Consultants | Bed and Bath Pantry - Port Antone",
"location": {
"lat": 87.2239,
"lon": -129.0506
},
"truncatedLatitute": 87,
"truncatedLongitude": -129
},
{
"_id": "26afb024-53c7-4e94-988c-5eede72277d5",
"name": "First Up Consultants | Microphone Bazaar - South Lexusland",
"location": {
"lat": -29.1866,
"lon": -112.7858
},
"truncatedLatitute": -29,
"truncatedLongitude": -112
},
{
"_id": "62438f5f-0c56-4a21-8c6c-6bfa479494ad",
"name": "First Up Consultants | Plumbing Supply Shoppe - New Ubaldofort",
"location": {
"lat": -0.2136,
"lon": 108.7466
},
"truncatedLatitute": 0,
"truncatedLongitude": 108
}
]