$min
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Definition
-
$min
-
The
$min
updates the value of the field to a specified value if the specified value is less than the current value of the field. The$min
operator can compare values of different types, using the BSON comparison order.To specify a
<field>
in an embedded document or in an array, use dot notation.
Behavior
If the field does not exists, the $min
operator sets the field to the specified value.
For comparisons between values of different types, such as a number and a null, $min
uses the BSON comparison order.
Examples
Use $min
to Compare Numbers
Consider the following document in the collection scores
:
The lowScore
for the document currently has the value 200
. The following operation uses $min
to compare 200
to the specified value 150
and updates the value of lowScore
to 150
since 150
is less than 200
:
The scores
collection now contains the following modified document:
The next operation has no effect since the current value of the field lowScore
, i.e 150
, is less than 250
:
The document remains unchanged in the scores
collection:
Use $min
to Compare Dates
Consider the following document in the collection tags
:
The following operation compares the current value of the dateEntered
field, i.e. ISODate("2013-10-01T05:00:00Z")
, with the specified date new Date("2013-09-25")
to determine whether to update the field:
The operation updates the dateEntered
field: