C100DBA CRUD Operations Practice Question
Which operator is used to perform a logical OR operation across multiple query conditions?
⚠ Common exam trap
Candidates sometimes confuse the $or operator with the $in operator. While both handle multiple conditions, $or is for distinct fields or complex expressions, whereas $in is for multiple values of a single field.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
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$or
The $or operator enables the evaluation of multiple conditions, returning documents that satisfy at least one of them. It is essential for complex filtering where data might fall into different categories. By nesting conditions within an $or array, developers can perform sophisticated queries that are not possible with simple key-value pairs, allowing for flexible data retrieval patterns in diverse application environments.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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$and
Why it's wrong here
$and is used for logical conjunction, where all specified conditions must be true for a document to be returned. It is generally unnecessary in most top-level queries because MongoDB implicitly performs an AND operation on multiple fields provided in a query document, making it redundant.
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$not
Why it's wrong here
$not is a logical inversion operator. It performs a bitwise or boolean negation on a specific expression. It does not combine multiple conditions into a single OR logic block. Using it for combining query filters will lead to incorrect query results, as it behaves quite differently.
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$or
Why this is correct
$or is the standard operator for logical disjunction. It accepts an array of expressions and returns documents that match any of the provided conditions. This is the correct choice for scenarios where a query needs to satisfy a variety of possibilities within the document model.
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$nor
Why it's wrong here
$nor is the logical NOR operator. It matches documents that fail to satisfy any of the conditions provided in the array. This is the inverse of what is required when looking for a logical OR match, as it excludes all matching documents from the final set.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official MongoDB exam blueprint
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