$setDifference
Reference group: Array aggregation expressions
What it does
Returns values in the first array but not the second.
Syntax
{$setDifference: [array1, array2]}
Use case
Find unmet requirements.
$setDifference: practical example
{ $project: { missing: { $setDifference: ["$requiredSkills", "$skills"] } } }💡 Explanation
Returns values in the first array but not the second.
When to use it
Find unmet requirements.
Key Takeaways
- Returns values in the first array but not the second.
- Typical use: Find unmet requirements.