Question 1,005 of 1,639
Mitigate threats using Microsoft SentinelmediumMultiple ChoiceObjective-mapped

Quick Answer

The answer is the `leftanti` join pattern, specifically `IdentityInfo | join kind=leftanti (SigninLogs | where TimeGenerated > ago(30d)) on UserPrincipalName`. This is correct because a `leftanti` join returns only rows from the left table (`IdentityInfo`) that have no matching rows in the right table (`SigninLogs` filtered to the last 30 days), directly isolating users who exist in the identity inventory but lack any sign-in record within that window. On the Microsoft Security Operations Analyst SC-200 exam, this question tests your ability to translate a detection requirement into the correct KQL join type—a common trap is confusing `leftanti` with `leftouter`, which would return all users with nulls instead of only the inactive ones. The search intent for "KQL leftanti join for inactive users" is perfectly served here because the pattern explicitly excludes active users. Memory tip: think "leftanti = left table minus the intersection"—it’s like a subtraction that leaves only the unmatched records.

SC-200 Mitigate threats using Microsoft Sentinel Practice Question

This SC-200 practice question tests your understanding of mitigate threats using microsoft sentinel. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

A SOC analyst is configuring an analytics rule in Microsoft Sentinel. The rule should run every hour and check for sign-ins from users who have been inactive for more than 30 days. The analyst uses the SigninLogs and IdentityInfo tables. Which KQL query pattern should be used to identify these users?

Question 1mediummultiple choice
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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

IdentityInfo | join kind=leftanti (SigninLogs | where TimeGenerated > ago(30d)) on UserPrincipalName

Option B is correct because it uses a `leftanti` join to return all rows from the `IdentityInfo` table that have no matching `UserPrincipalName` in the `SigninLogs` table for the last 30 days. This directly identifies users who are in the identity inventory but have not signed in within the past 30 days, which is the exact requirement for detecting inactive users.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • union IdentityInfo, SigninLogs | where TimeGenerated > ago(30d) | summarize by UserPrincipalName

    Why it's wrong here

    This approach combines both tables and then filters for recent records, which would not identify users with no recent sign-ins.

  • IdentityInfo | join kind=leftanti (SigninLogs | where TimeGenerated > ago(30d)) on UserPrincipalName

    Why this is correct

    Correct. The left anti join returns all rows from IdentityInfo that do not have a matching UserPrincipalName in the recent SigninLogs, effectively finding inactive users.

    Related concept

    Read the scenario before looking for a memorised answer.

  • SigninLogs | where TimeGenerated > ago(30d) | summarize by UserPrincipalName | join kind=rightanti IdentityInfo on UserPrincipalName

    Why it's wrong here

    This would return users in SigninLogs that are not in IdentityInfo, which is the opposite of what is needed.

  • SigninLogs | where TimeGenerated < ago(30d) | summarize by UserPrincipalName

    Why it's wrong here

    This filters for sign-ins older than 30 days, which does not identify inactive users; it just returns historical sign-in records.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates often confuse `leftanti` with `rightanti` or `leftouter` joins, mistakenly thinking that summarizing sign-ins first and then joining will correctly identify inactive users, when in fact the direction of the anti-join determines which table's unmatched rows are returned.

Detailed technical explanation

How to think about this question

The `leftanti` join in KQL is semantically equivalent to a `NOT EXISTS` subquery in SQL, returning only rows from the left table where no match exists in the right table. In this scenario, the `IdentityInfo` table is the authoritative list of all users, and the `SigninLogs` table filtered to the last 30 days provides the set of active users; the `leftanti` join efficiently identifies users absent from that active set. A real-world consideration is that the `IdentityInfo` table is updated periodically (e.g., daily) and may contain stale or duplicate entries, so the rule should also account for potential data latency or use `distinct` to avoid false positives.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.

What to study next

Got this wrong? Here's your next step.

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FAQ

Questions learners often ask

What does this SC-200 question test?

Mitigate threats using Microsoft Sentinel — This question tests Mitigate threats using Microsoft Sentinel — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: IdentityInfo | join kind=leftanti (SigninLogs | where TimeGenerated > ago(30d)) on UserPrincipalName — Option B is correct because it uses a `leftanti` join to return all rows from the `IdentityInfo` table that have no matching `UserPrincipalName` in the `SigninLogs` table for the last 30 days. This directly identifies users who are in the identity inventory but have not signed in within the past 30 days, which is the exact requirement for detecting inactive users.

What should I do if I get this SC-200 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jun 11, 2026

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