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MongoDB Complete Course / Query Operators

$in operator

Learn $in operator in MongoDB through the exact construct, a dedicated example, a boundary case, and a mastery check.

10 min read • Beginner

$in operator is an atomic MongoDB lesson inside Query Operators. The example uses the specific syntax, command, API, instruction, or language rule named by this lesson.

Study the construct itself, then change one relevant input and predict the result before running it. That keeps this lesson focused on $in operator rather than on generic MongoDB syntax.

Topic-specific example

mongodb-02-03.js
javascript Try It Live
db.users.find({ role: { $in: ["admin","editor"] } })
Edge case / engineering note

Test $in operator with an empty result, NULL/missing value, duplicate key, or concurrent operation where relevant; database behavior should be verified at the boundary shown by this example.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content