skip method for offset in MongoDB - Step-by-Step Execution

Concept Flow - skip method for offset

Start Query

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Apply Filter

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Sort Documents

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Skip N Documents

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Return Remaining Documents

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End

The skip method tells MongoDB to ignore a number of documents at the start of the result, then return the rest.

Execution Sample

MongoDB

db.collection.find().sort({age: 1}).skip(3).limit(2)

This query sorts documents by age ascending, skips the first 3, then returns the next 2 documents.

Execution Table

Step	Action	Documents Before	Documents After	Notes
1	Start with all documents	[{age: 20}, {age: 25}, {age: 30}, {age: 35}, {age: 40}]	[{age: 20}, {age: 25}, {age: 30}, {age: 35}, {age: 40}]	Initial collection
2	Sort by age ascending	[{age: 20}, {age: 25}, {age: 30}, {age: 35}, {age: 40}]	[{age: 20}, {age: 25}, {age: 30}, {age: 35}, {age: 40}]	Already sorted in this example
3	Skip first 3 documents	[{age: 20}, {age: 25}, {age: 30}, {age: 35}, {age: 40}]	[{age: 35}, {age: 40}]	Documents with age 20, 25, 30 skipped
4	Limit to 2 documents	[{age: 35}, {age: 40}]	[{age: 35}, {age: 40}]	Only 2 documents returned
5	End	[{age: 35}, {age: 40}]	[{age: 35}, {age: 40}]	Query complete

💡 After skipping 3 documents, only documents from index 3 onward are returned, limited to 2.

Variable Tracker

Variable	Start	After Sort	After Skip	After Limit	Final
documents	[{age: 20}, {age: 25}, {age: 30}, {age: 35}, {age: 40}]	[{age: 20}, {age: 25}, {age: 30}, {age: 35}, {age: 40}]	[{age: 35}, {age: 40}]	[{age: 35}, {age: 40}]	[{age: 35}, {age: 40}]

Key Moments - 3 Insights

Why does skip(3) remove the first three documents instead of the last three?

skip(3) tells MongoDB to ignore the first 3 documents in the sorted list, so it removes documents at the start, not the end. See execution_table row 3 where the first three documents are skipped.

What happens if skip number is larger than total documents?

If skip is larger than the number of documents, no documents remain to return. The result will be empty. This is because all documents are skipped.

Does skip change the order of documents?

No, skip only removes documents from the start after sorting. The order of remaining documents stays the same. See execution_table rows 2 and 3.

Visual Quiz - 3 Questions

Look at the execution_table, what documents remain after the skip step (Step 3)?

A [{age: 20}, {age: 25}, {age: 30}]

B [{age: 35}, {age: 40}]

C [{age: 25}, {age: 30}, {age: 35}]

D [{age: 20}, {age: 25}, {age: 30}, {age: 35}, {age: 40}]

💡 Hint

Check the 'Documents After' column at Step 3 in the execution_table.

At which step does the query limit the number of documents returned?

A Step 2

B Step 3

C Step 4

D Step 5

💡 Hint

Look for the action 'Limit to 2 documents' in the execution_table.

If skip(0) was used instead of skip(3), how would the documents after skip change at Step 3?

A All documents would remain, same as before skip

B Only first 3 documents would remain

C No documents would remain

D Only last 2 documents would remain

💡 Hint

skip(0) means skip zero documents, so no documents are removed at Step 3.

Concept Snapshot

skip(n) in MongoDB skips the first n documents in the query result.
Use it after sorting to offset results.
Commonly combined with limit() to paginate.
If n is larger than total docs, result is empty.
Order of remaining docs stays unchanged.

Full Transcript

The skip method in MongoDB is used to ignore a number of documents at the start of the query result. First, the query finds all documents and applies any filters. Then it sorts the documents if specified. After sorting, skip(n) removes the first n documents from the result. The remaining documents are returned, often limited by limit(). For example, if we have documents with ages 20, 25, 30, 35, and 40, and we skip 3, the first three documents (ages 20, 25, 30) are ignored. The query then returns documents starting from age 35 onward. This is useful for pagination to show results starting from a certain offset. If skip is zero, no documents are skipped. If skip is larger than the number of documents, the result is empty. The order of documents after skipping remains the same as after sorting.