$where
Reference group: Query filter operators
What it does
Runs server-side JavaScript predicate logic in supported configurations.
Syntax
{$where: JavaScript expression}
Use case
Legacy diagnostics only.
Important notes
Usually avoid; can be slow or restricted. Prefer $expr.
$where: practical example
db.legacy.find({ $where: "this.a > this.b" })💡 Explanation
Runs server-side JavaScript predicate logic in supported configurations.
When to use it
Legacy diagnostics only.
Caution
Usually avoid; can be slow or restricted. Prefer
$expr.Key Takeaways
- Runs server-side JavaScript predicate logic in supported configurations.
- Typical use: Legacy diagnostics only.