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- $gt (aggregation)
$gt (aggregation)¶
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Definition¶
- $gt¶
Compares two values and returns:
- true when the first value is greater than the second value.
- false when the first value is less than or equivalent to the second value.
The $gt compares both value and type, using the specified BSON comparison order for values of different types.
$gt has the following syntax:
{ $gt: [ <expression1>, <expression2> ] }
For more information on expressions, see Expressions.
Example¶
Consider an inventory collection with the following documents:
{ "_id" : 1, "item" : "abc1", description: "product 1", qty: 300 }
{ "_id" : 2, "item" : "abc2", description: "product 2", qty: 200 }
{ "_id" : 3, "item" : "xyz1", description: "product 3", qty: 250 }
{ "_id" : 4, "item" : "VWZ1", description: "product 4", qty: 300 }
{ "_id" : 5, "item" : "VWZ2", description: "product 5", qty: 180 }
The following operation uses the $gt operator to determine if qty is greater than 250:
db.inventory.aggregate(
[
{
$project:
{
item: 1,
qty: 1,
qtyGt250: { $gt: [ "$qty", 250 ] },
_id: 0
}
}
]
)
The operation returns the following results:
{ "item" : "abc1", "qty" : 300, "qtyGt250" : true }
{ "item" : "abc2", "qty" : 200, "qtyGt250" : false }
{ "item" : "xyz1", "qty" : 250, "qtyGt250" : false }
{ "item" : "VWZ1", "qty" : 300, "qtyGt250" : true }
{ "item" : "VWZ2", "qty" : 180, "qtyGt250" : false }