$ifNull (aggregation)
$ifNull
is used to evaluate an expression and returns value. If the expression
evaluates to a null value that time it returns to replacement expression value.
Syntax:
{ $ifNull: [ “expression”, “replacement-expression-if-value-is-null”]
}
For example,
db.customers.aggregate([{
$project: {CustID: 1001,
CustomerCode: { $ifNull: [ "$CustomerCode ", "Pending Approval" ] } }
} ]);
In the above example, if customer code is null
that time the expression returns to “Pending
Approval” (as per you).
Thank you!
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