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Improve Sort & Limit section with clearer explanations and examples
- Added explanatory text for sort(), limit(), and skip() - Improved scenario descriptions and renamed variables for better readability - Adjusted examples to better match the workshop flow - Added documentation links with UTM tracking - Removed duplicated exercises already covered in the Find section
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‎java/20_sort_limit.ipynb‎

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"id": "3b936925-e295-489a-b508-2b99c0160217",
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"metadata": {},
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"source": [
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"# CRUD: Project, Sort & Limit\n",
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" "
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"# CRUD: Sort & Limit\n",
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"\n",
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"## What can `sort()` and `limit()` do?\n",
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"\n",
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"The [`sort()`](https://www.mongodb.com/docs/drivers/java/sync/current/crud/query-documents/sort/?utm_campaign=devrel&utm_source=third-part-content&utm_medium=cta&utm_content=crud-operations-java-workshop&utm_term=ricardo.mello) and [`limit()`](https://www.mongodb.com/docs/drivers/java/sync/current/crud/query-documents/limit/?utm_campaign=devrel&utm_source=third-part-content&utm_medium=cta&utm_content=crud-operations-java-workshop&utm_term=ricardo.mello) operations let us control the order and number of documents returned by a query.\n",
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"\n",
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"In this section, we will sort documents in ascending or descending order and limit how many results are returned from the collection."
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]
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},
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{
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"cell_type": "markdown",
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"id": "13926b8c",
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"metadata": {},
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"source": [
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"## Startup code"
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"## Startup code\n",
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"\n",
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"This cell imports the MongoDB Java Driver and helper classes, establishes the connection to MongoDB, and initializes the `library` database and `books` collection used throughout the CRUD examples."
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]
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},
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{
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"import com.mongodb.client.model.Sorts;\n",
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"import com.mongodb.client.model.Projections;\n",
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"\n",
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"import static com.mongodb.client.model.Projections.fields;\n",
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"import static com.mongodb.client.model.Projections.excludeId;\n",
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"import static com.mongodb.client.model.Projections.include;\n",
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"\n",
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"import static com.mongodb.client.model.Sorts.ascending;\n",
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"import static com.mongodb.client.model.Sorts.descending;\n",
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"import static com.mongodb.client.model.Filters.eq;\n",
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"\n",
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"import static com.mongodb.client.model.Filters.lte;\n",
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"\n",
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"import org.bson.Document;\n",
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"import org.bson.conversions.Bson;\n",
@@ -58,6 +71,10 @@
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"import java.util.ArrayList;\n",
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"import java.util.List;\n",
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"\n",
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"// Configure SLF4J Simple Logger to suppress MongoDB driver logs in the notebook output.\n",
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"System.setProperty(\"org.slf4j.simpleLogger.defaultLogLevel\", \"off\");\n",
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"System.setProperty(\"org.slf4j.simpleLogger.log.org.mongodb.driver\", \"off\");\n",
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"\n",
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"// Set your connection String\n",
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"String connectionString = \"mongodb://admin:mongodb@localhost:27017/\";\n",
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"\n",
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"id": "automatic-fisher",
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"metadata": {},
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"source": [
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"## Sort books by descending number of pages\n"
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"## Sort books by descending number of pages\n",
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"\n",
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"In this example, we use [`lte()`](https://www.mongodb.com/docs/manual/reference/operator/query/lte/?utm_campaign=devrel&utm_source=third-part-content&utm_medium=cta&utm_content=crud-operations-java-workshop&utm_term=ricardo.mello) to filter books published before or in `1930`, project only the `title` and `pages` fields, and use [`sort()`](https://www.mongodb.com/docs/drivers/java/sync/current/crud/query-documents/sort/?utm_campaign=devrel&utm_source=third-part-content&utm_medium=cta&utm_content=crud-operations-java-workshop&utm_term=ricardo.mello) to order the results by the number of pages in descending order."
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]
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},
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{
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},
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"outputs": [],
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"source": [
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"Bson projection = Projections.include(\"title\", \"pages\");\n",
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"\n",
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"FindIterable<Document> cursor = books \n",
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" .find() // empty filter: all books \n",
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" .projection(projection) // projection \n",
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" .sort(Sorts.descending(\"pages\")); // sort by pages descending \n",
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" .find(lte(\"year\", 1930)) \n",
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" .projection(\n",
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" fields(excludeId(), include(\"title\", \"pages\"))\n",
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" )\n",
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" .sort(descending(\"pages\")); \n",
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"\n",
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"for (Document book : cursor) { \n",
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" System.out.println(book.toJson()); \n",
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"} "
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"}"
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]
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},
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{
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"cell_type": "markdown",
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"id": "handled-symbol",
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"metadata": {},
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"source": [
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"## Limit"
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"## Retrieve the top 5 longest books\n",
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"\n",
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"In this example, we retrieve all books, project only the `title` and `pages` fields, sort the results by the number of pages in descending order, and use [`limit()`](https://www.mongodb.com/docs/drivers/java/sync/current/crud/query-documents/limit/?utm_campaign=devrel&utm_source=third-part-content&utm_medium=cta&utm_content=crud-operations-java-workshop&utm_term=ricardo.mello) to return only the first 5 documents."
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]
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},
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{
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},
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"outputs": [],
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"source": [
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"Bson projection = Projections.include(\"title\", \"pages\"); // projection \n",
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"\n",
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"FindIterable<Document> cursor = books \n",
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" .find() // empty filter: all books \n",
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" .projection(projection) // projection \n",
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" .sort(Sorts.descending(\"pages\")) // sort by pages descending \n",
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" .limit(5); // limit to 5 documents\n",
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" .find() \n",
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" .projection(include(\"title\", \"pages\")) \n",
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" .sort(descending(\"pages\")) \n",
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" .limit(5); \n",
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"\n",
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"for (Document book : cursor) { \n",
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" System.out.println(book.toJson()); \n",
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"id": "9f6caab3",
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"metadata": {},
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"source": [
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"## Chaining methods with find"
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"## Skip the first 180 books and retrieve the next 5\n",
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"\n",
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"In this example, we project only the `title` and `pages` fields, sort the books by the number of pages in ascending order, use [`skip()`](https://www.mongodb.com/docs/drivers/java/sync/current/crud/query-documents/skip/?utm_campaign=devrel&utm_source=third-part-content&utm_medium=cta&utm_content=crud-operations-java-workshop&utm_term=ricardo.mello) to ignore the first 180 matching documents, and return the next 5 results."
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]
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{
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},
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"outputs": [],
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"source": [
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"Bson projection = Projections.include(\"title\", \"pages\"); // projection \n",
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"Bson projection = Projections.include(\"title\", \"pages\");\n",
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"\n",
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"FindIterable<Document> cursor = books \n",
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" .find() // empty filter: all books \n",
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" .projection(projection) // projection \n",
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" .sort(Sorts.descending(\"pages\")) // sort by pages descending \n",
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" .skip(4) // skip first 4 documents\n",
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" .limit(5); // limit to 5 documents\n",
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"FindIterable<Document> cursor = books\n",
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" .find()\n",
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" .projection(projection)\n",
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" .sort(ascending(\"pages\"))\n",
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" .skip(180)\n",
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" .limit(5);\n",
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"\n",
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"for (Document book : cursor) { \n",
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" System.out.println(book.toJson()); \n",
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"} "
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"for (Document book : cursor) {\n",
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" System.out.println(book.toJson());\n",
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"}"
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]
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},
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{
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},
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{
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"cell_type": "markdown",
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"id": "00153c48",
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"id": "1714facc",
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"metadata": {},
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"source": [
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"### Retrieve only the title field for all books.\n",
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"### Find the first 10 books alphabetically by title\n",
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"\n",
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"[Solution here](https://mongodb-developer.github.io/sql-to-query-api-lab/docs/CRUD/SELECT#-1-retrieve-only-the-title-field-for-all-books)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"id": "4a4f8e26",
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"metadata": {
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"vscode": {
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"languageId": "java"
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}
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},
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"outputs": [],
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"source": [
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"// type your code here"
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]
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},
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{
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"cell_type": "markdown",
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"id": "ffea41f8",
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"metadata": {},
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"source": [
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"### Retrieve all fields except _id and authors for books in the \"History\" genre.\n",
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"_Hint: Use `sort()` with ascending order on the `title` field and combine it with `limit()` to return only 10 documents._\n",
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"\n",
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"[Solution here](https://mongodb-developer.github.io/sql-to-query-api-lab/docs/CRUD/SELECT#-2-retrieve-all-fields-except-_id-and-authors-for-books-in-the-history-genre)"
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"[Solution here](https://mongodb-developer.github.io/sql-to-query-api-lab/docs/CRUD/ORDER-LIMIT#-1-find-the-first-10-books-alphabetically-by-title?utm_campaign=devrel&utm_source=third-part-content&utm_medium=cta&utm_content=crud-operations-java-workshop&utm_term=ricardo.mello)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"id": "f02579f7",
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"id": "5409c76d",
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"metadata": {
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"vscode": {
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"languageId": "java"
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}
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},
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"outputs": [],
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"source": [
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"// type your code here\n"
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"//TYPE YOUR CODE HERE\n",
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"books.find()\n",
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" .sort(<REPLACE_WITH_SORT>)\n",
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" .limit(<REPLACE_WITH_LIMIT>)\n",
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" .forEach(book -> System.out.println(\"Book: \" + book.toJson()));"
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]
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},
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{
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"cell_type": "markdown",
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"id": "1714facc",
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"id": "bc2d6bee",
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"metadata": {},
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"source": [
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"### Find the first 10 books alphabetically by title.\n",
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"## Summary\n",
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"\n",
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"[Solution here](https://mongodb-developer.github.io/sql-to-query-api-lab/docs/CRUD/ORDER-LIMIT#-1-find-the-first-10-books-alphabetically-by-title)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"id": "5409c76d",
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"metadata": {
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"vscode": {
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"languageId": "java"
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}
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},
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"outputs": [],
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"source": [
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"// type your code here\n"
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"In this section, we learned how to use `sort()`, `skip()`, and `limit()` to control the order and number of documents returned by a query. These operations are commonly combined with `find()` to build more efficient and readable queries."
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]
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}
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],

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