$toBool
The $toBool operator converts an expression into a Boolean type
$toBool
The $toBool operator converts an expression into a Boolean value. Boolean values are returned as is without a conversion. Nonzero numeric values are converted to true while Decimal, Long, Double or Int values of 0 are converted to false. All other data types are converted to true.
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: Convert a Double value into a Boolean value
To convert the value of the latitude field from a double to a boolean, run a query using the $toBool operator on the field to make the conversion. Positive numeric values are converted to true.
db.stores.aggregate([{
$match: {
_id: "b0107631-9370-4acd-aafa-8ac3511e623d"
}
}, {
$project: {
originalLatitude: "$location.lat",
latitudeAsBool: {
$toBool: "$location.lat"
}
}
}])This query returns the following result:
[
{
"_id": "b0107631-9370-4acd-aafa-8ac3511e623d",
"originalLatitude": 72.8377,
"latitudeAsBool": true
}
]Example 2: Convert a String value into a Boolean value
To convert the value of the _id field from a string to a boolean, run a query using the $toBool value to make the conversion. String values are converted to true.
db.stores.aggregate([{
$match: {
_id: "b0107631-9370-4acd-aafa-8ac3511e623d"
}
}, {
$project: {
originalId: "$_id",
idAsBool: {
$toBool: "$_id"
}
}
}])This query returns the following result:
[
{
"_id": "b0107631-9370-4acd-aafa-8ac3511e623d",
"originalId": "b0107631-9370-4acd-aafa-8ac3511e623d",
"idAsBool": true
}
]Example 3: Convert an Int value into a Boolean value
To convert the value of the sales.totalSales field from integer to boolean, run a query using the $toBool operator to make the conversion. Positive numeric values are converted to true.
db.stores.aggregate([{
$match: {
_id: "b0107631-9370-4acd-aafa-8ac3511e623d"
}
}, {
$project: {
originalTotalSales: "$sales.totalSales",
totalSalesAsBool: {
$toBool: "$sales.totalSales"
}
}
}])This query returns the following result:
[
{
"_id": "b0107631-9370-4acd-aafa-8ac3511e623d",
"originalTotalSales": 9366,
"totalSalesAsBool": true
}
]This table delineates the expected behavior of the $toBool operator based on the data type of the input expression.
| Value Type | Behavior/Output |
|---|---|
| Boolean value true | Output -> true |
| Boolean value false | Output -> false |
| Any Double, Int, Long, or Decimal value | Output -> true |
| Any ISODate value | Output -> true |
| Null value | Output -> null |