{"id":2457,"date":"2025-03-07T22:58:21","date_gmt":"2025-03-07T14:58:21","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=2457"},"modified":"2025-03-07T22:58:21","modified_gmt":"2025-03-07T14:58:21","slug":"mongodb-%e8%81%9a%e5%90%88%ef%bc%88aggregation%ef%bc%89","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/03\/07\/mongodb-%e8%81%9a%e5%90%88%ef%bc%88aggregation%ef%bc%89\/","title":{"rendered":"MongoDB \u805a\u5408\uff08Aggregation\uff09"},"content":{"rendered":"\n

MongoDB \u805a\u5408\uff08Aggregation\uff09<\/strong> \u901a\u8fc7 aggregate()<\/code> \u65b9\u6cd5\u5bf9\u6587\u6863\u8fdb\u884c\u590d\u6742\u7684\u6570\u636e\u5904\u7406\uff0c\u5982\u5206\u7ec4\u3001\u8fc7\u6ee4\u3001\u6392\u5e8f\u3001\u8ba1\u7b97\u7edf\u8ba1\u503c<\/strong>\u7b49\uff0c\u7c7b\u4f3c SQL \u7684 GROUP BY<\/code> \u548c HAVING<\/code> \u8bed\u53e5\u3002<\/p>\n\n\n\n

\n\n\n\n

1. \u805a\u5408\u7ba1\u9053\uff08Aggregation Pipeline\uff09<\/strong><\/h3>\n\n\n\n

MongoDB \u91c7\u7528 Pipeline\uff08\u7ba1\u9053\uff09\u673a\u5236<\/strong>\uff0c\u591a\u4e2a\u64cd\u4f5c\u53ef\u4ee5\u4f9d\u6b21\u5904\u7406\u6570\u636e<\/strong>\uff0c\u6bcf\u4e2a\u64cd\u4f5c\u7684\u8f93\u51fa\u4f5c\u4e3a\u4e0b\u4e00\u4e2a\u64cd\u4f5c\u7684\u8f93\u5165\u3002<\/p>\n\n\n\n

db.collection.aggregate([\n  { stage1 },\n  { stage2 },\n  { stage3 }\n])<\/code><\/pre>\n\n\n\n
    \n
  • \u6bcf\u4e2a stage\uff08\u9636\u6bb5\uff09<\/code> \u662f\u4e00\u4e2a\u6570\u636e\u5904\u7406\u6b65\u9aa4<\/strong>\uff0cMongoDB \u4f9d\u6b21\u6267\u884c\u3002<\/li>\n<\/ul>\n\n\n\n
    \n\n\n\n
    2. \u4e3b\u8981\u805a\u5408\u64cd\u4f5c\u7b26<\/strong><\/h3>\n\n\n\n
    \u64cd\u4f5c\u7b26<\/strong><\/th>\u4f5c\u7528<\/strong><\/th><\/tr><\/thead>
    $match<\/code><\/td>\u8fc7\u6ee4\u6570\u636e\uff08\u7c7b\u4f3c SQL WHERE<\/code>\uff09<\/td><\/tr>
    $group<\/code><\/td>\u5206\u7ec4\uff08\u7c7b\u4f3c SQL GROUP BY<\/code>\uff09<\/td><\/tr>
    $sort<\/code><\/td>\u6392\u5e8f\uff08\u7c7b\u4f3c SQL ORDER BY<\/code>\uff09<\/td><\/tr>
    $project<\/code><\/td>\u6307\u5b9a\u8fd4\u56de\u5b57\u6bb5\uff08\u7c7b\u4f3c SQL SELECT<\/code>\uff09<\/td><\/tr>
    $limit<\/code><\/td>\u9650\u5236\u8fd4\u56de\u6570\u91cf\uff08\u7c7b\u4f3c SQL LIMIT<\/code>\uff09<\/td><\/tr>
    $skip<\/code><\/td>\u8df3\u8fc7\u6307\u5b9a\u6570\u91cf\u7684\u6587\u6863\uff08\u7c7b\u4f3c SQL OFFSET<\/code>\uff09<\/td><\/tr>
    $count<\/code><\/td>\u7edf\u8ba1\u603b\u6570<\/td><\/tr>
    $unwind<\/code><\/td>\u62c6\u5206\u6570\u7ec4<\/td><\/tr>
    $lookup<\/code><\/td>\u5173\u8054\u67e5\u8be2\uff08\u7c7b\u4f3c SQL JOIN<\/code>\uff09<\/td><\/tr>
    $addFields<\/code><\/td>\u6dfb\u52a0\u8ba1\u7b97\u5b57\u6bb5<\/td><\/tr>
    $set<\/code><\/td>\u4fee\u6539\u6216\u65b0\u589e\u5b57\u6bb5\uff08MongoDB 4.2+\uff09<\/td><\/tr>
    $unset<\/code><\/td>\u79fb\u9664\u5b57\u6bb5<\/td><\/tr>
    $merge<\/code><\/td>\u7ed3\u679c\u5b58\u5165\u65b0\u96c6\u5408<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
    \n\n\n\n
    3. \u8fc7\u6ee4\u6570\u636e\uff08$match\uff09<\/strong><\/h3>\n\n\n\n
    $match<\/code> \u4f5c\u7528\u7c7b\u4f3c WHERE<\/code>\uff0c\u7528\u4e8e\u7b5b\u9009\u7b26\u5408\u6761\u4ef6\u7684\u6570\u636e<\/strong>\uff0c\u51cf\u5c11\u540e\u7eed\u5904\u7406\u7684\u6570\u636e\u91cf\u3002<\/p>\n\n\n\n
    \u793a\u4f8b<\/strong><\/h4>\n\n\n\n
    \u67e5\u8be2 status<\/code> \u4e3a \"active\"<\/code> \u4e14 price > 100<\/code> \u7684\u5546\u54c1\uff1a<\/p>\n\n\n\n
    db.products.aggregate([\n  { $match: { status: \"active\", price: { $gt: 100 } } }\n])<\/code><\/pre>\n\n\n\n
    \u7b49\u4ef7\u4e8e SQL\uff1a<\/strong><\/p>\n\n\n\n
    SELECT * FROM products WHERE status = 'active' AND price > 100;<\/code><\/pre>\n\n\n\n
    \n\n\n\n
    4. \u5206\u7ec4\u7edf\u8ba1\uff08$group\uff09<\/strong><\/h3>\n\n\n\n
    $group<\/code> \u7c7b\u4f3c SQL GROUP BY<\/code>\uff0c\u53ef\u4ee5\u6309\u7167\u67d0\u5b57\u6bb5\u5206\u7ec4\uff0c\u5e76\u8ba1\u7b97\u7edf\u8ba1\u503c<\/strong>\u3002<\/p>\n\n\n\n
    \u793a\u4f8b<\/strong><\/h4>\n\n\n\n
    \u6309 category<\/code> \u5206\u7ec4\uff0c\u7edf\u8ba1\u6bcf\u4e2a\u7c7b\u522b\u7684\u5546\u54c1\u6570\u91cf\uff1a<\/p>\n\n\n\n
    db.products.aggregate([\n  { $group: { _id: \"$category\", count: { $sum: 1 } } }\n])<\/code><\/pre>\n\n\n\n
      \n
    • _id: \"$category\"<\/code> \u2192 \u6309 category<\/code> \u5206\u7ec4\u3002<\/li>\n\n\n\n
    • count: { $sum: 1 }<\/code> \u2192 \u7edf\u8ba1\u8be5\u5206\u7ec4\u5185\u7684\u6587\u6863\u6570\u3002<\/li>\n<\/ul>\n\n\n\n
      \u7b49\u4ef7\u4e8e SQL\uff1a<\/strong><\/p>\n\n\n\n
      SELECT category, COUNT(*) FROM products GROUP BY category;<\/code><\/pre>\n\n\n\n
      \u5176\u4ed6\u5e38\u7528\u7edf\u8ba1\u8fd0\u7b97<\/strong><\/h4>\n\n\n\n
      \u64cd\u4f5c\u7b26<\/strong><\/th>\u4f5c\u7528<\/strong><\/th><\/tr><\/thead>
      $sum<\/code><\/td>\u8ba1\u7b97\u603b\u548c<\/td><\/tr>
      $avg<\/code><\/td>\u8ba1\u7b97\u5e73\u5747\u503c<\/td><\/tr>
      $max<\/code><\/td>\u8ba1\u7b97\u6700\u5927\u503c<\/td><\/tr>
      $min<\/code><\/td>\u8ba1\u7b97\u6700\u5c0f\u503c<\/td><\/tr>
      $first<\/code><\/td>\u53d6\u5206\u7ec4\u4e2d\u7684\u7b2c\u4e00\u4e2a\u503c<\/td><\/tr>
      $last<\/code><\/td>\u53d6\u5206\u7ec4\u4e2d\u7684\u6700\u540e\u4e00\u4e2a\u503c<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
      \n\n\n\n
      5. \u6307\u5b9a\u8fd4\u56de\u5b57\u6bb5\uff08$project\uff09<\/strong><\/h3>\n\n\n\n
      $project<\/code> \u7528\u4e8e\u6307\u5b9a\u9700\u8981\u8fd4\u56de\u7684\u5b57\u6bb5<\/strong>\uff0c\u7c7b\u4f3c SQL SELECT<\/code>\u3002<\/p>\n\n\n\n
      \u793a\u4f8b<\/strong><\/h4>\n\n\n\n
      \u4ec5\u8fd4\u56de name<\/code> \u548c price<\/code> \u5b57\u6bb5\uff1a<\/p>\n\n\n\n
      db.products.aggregate([\n  { $project: { name: 1, price: 1, _id: 0 } }\n])<\/code><\/pre>\n\n\n\n
        \n
      • 1<\/code> \u8868\u793a\u663e\u793a<\/strong>\u8be5\u5b57\u6bb5\u3002<\/li>\n\n\n\n
      • _id: 0<\/code> \u8868\u793a\u9690\u85cf _id<\/code> \u5b57\u6bb5<\/strong>\uff08MongoDB \u9ed8\u8ba4\u4f1a\u8fd4\u56de _id<\/code>\uff09\u3002<\/li>\n<\/ul>\n\n\n\n
        \u7b49\u4ef7\u4e8e SQL\uff1a<\/strong><\/p>\n\n\n\n
        SELECT name, price FROM products;<\/code><\/pre>\n\n\n\n
        \u8ba1\u7b97\u65b0\u5b57\u6bb5<\/strong><\/h4>\n\n\n\n
        \u4f7f\u7528 $project<\/code> \u8ba1\u7b97\u65b0\u5b57\u6bb5\uff1a<\/p>\n\n\n\n
        db.products.aggregate([\n  { $project: { name: 1, priceWithTax: { $multiply: [\"$price\", 1.1] } } }\n])<\/code><\/pre>\n\n\n\n
          \n
        • priceWithTax<\/code> \u662f\u8ba1\u7b97\u540e\u7684\u65b0\u5b57\u6bb5\uff08\u5546\u54c1\u4ef7\u683c \u00d7 1.1\uff09\u3002<\/li>\n<\/ul>\n\n\n\n
          \n\n\n\n
          6. \u6392\u5e8f\uff08$sort\uff09<\/strong><\/h3>\n\n\n\n
          $sort<\/code> \u7c7b\u4f3c SQL ORDER BY<\/code>\uff0c\u7528\u4e8e\u5bf9\u7ed3\u679c\u6392\u5e8f<\/strong>\u3002<\/p>\n\n\n\n
          \u793a\u4f8b<\/strong><\/h4>\n\n\n\n
          \u6309 price<\/code> \u964d\u5e8f\u6392\u5e8f\uff1a<\/p>\n\n\n\n
          db.products.aggregate([\n  { $sort: { price: -1 } }\n])<\/code><\/pre>\n\n\n\n
            \n
          • 1<\/code> \u8868\u793a\u5347\u5e8f<\/strong>\uff08ASC\uff09\u3002<\/li>\n\n\n\n
          • -1<\/code> \u8868\u793a\u964d\u5e8f<\/strong>\uff08DESC\uff09\u3002<\/li>\n<\/ul>\n\n\n\n
            \u7b49\u4ef7\u4e8e SQL\uff1a<\/strong><\/p>\n\n\n\n
            SELECT * FROM products ORDER BY price DESC;<\/code><\/pre>\n\n\n\n
            \n\n\n\n
            7. \u9650\u5236 & \u8df3\u8fc7\uff08$limit & $skip\uff09<\/strong><\/h3>\n\n\n\n
              \n
            • $limit<\/code> \u2192 \u9650\u5236\u8fd4\u56de\u6570\u91cf<\/strong>\u3002<\/li>\n\n\n\n
            • $skip<\/code> \u2192 \u8df3\u8fc7\u6307\u5b9a\u6570\u91cf\u7684\u6587\u6863<\/strong>\uff08\u901a\u5e38\u7528\u4e8e\u5206\u9875\uff09\u3002<\/li>\n<\/ul>\n\n\n\n
              \u793a\u4f8b<\/strong><\/h4>\n\n\n\n
              \u83b7\u53d6\u7b2c 2 \u9875\uff0c\u6bcf\u9875 5 \u6761\u6570\u636e<\/strong>\uff1a<\/p>\n\n\n\n
              db.products.aggregate([\n  { $skip: 5 },  \/\/ \u8df3\u8fc7\u524d 5 \u6761\n  { $limit: 5 }  \/\/ \u83b7\u53d6 5 \u6761\n])<\/code><\/pre>\n\n\n\n
              \u7b49\u4ef7\u4e8e SQL\uff1a<\/strong><\/p>\n\n\n\n
              SELECT * FROM products LIMIT 5 OFFSET 5;<\/code><\/pre>\n\n\n\n
              \n\n\n\n
              8. \u62c6\u5206\u6570\u7ec4\uff08$unwind\uff09<\/strong><\/h3>\n\n\n\n
              $unwind<\/code> \u5c06\u6570\u7ec4\u5b57\u6bb5\u62c6\u5206\u6210\u591a\u884c\u6570\u636e<\/strong>\u3002<\/p>\n\n\n\n
              \u793a\u4f8b<\/strong><\/h4>\n\n\n\n
              \u5047\u8bbe orders<\/code> \u96c6\u5408\u7684 items<\/code> \u5b57\u6bb5\u662f\u6570\u7ec4\uff1a<\/p>\n\n\n\n
              { _id: 1, customer: \"Alice\", items: [\"Apple\", \"Banana\"] }\n{ _id: 2, customer: \"Bob\", items: [\"Orange\"] }<\/code><\/pre>\n\n\n\n
              \u4f7f\u7528 $unwind<\/code> \u62c6\u5206\uff1a<\/p>\n\n\n\n
              db.orders.aggregate([\n  { $unwind: \"$items\" }\n])<\/code><\/pre>\n\n\n\n
              \u7ed3\u679c\uff1a<\/p>\n\n\n\n
              { _id: 1, customer: \"Alice\", items: \"Apple\" }\n{ _id: 1, customer: \"Alice\", items: \"Banana\" }\n{ _id: 2, customer: \"Bob\", items: \"Orange\" }<\/code><\/pre>\n\n\n\n
              \u7b49\u4ef7\u4e8e SQL \u4e00\u5bf9\u591a\u62c6\u5206<\/strong>\u3002<\/p>\n\n\n\n
              \n\n\n\n
              9. \u5173\u8054\u67e5\u8be2\uff08$lookup\uff0c\u7c7b\u4f3c SQL JOIN\uff09<\/strong><\/h3>\n\n\n\n
              MongoDB \u6ca1\u6709\u5916\u952e\uff0c\u4f46\u53ef\u4ee5\u4f7f\u7528 $lookup<\/code> \u8fdb\u884c\u7c7b\u4f3c SQL JOIN<\/code><\/strong> \u7684\u67e5\u8be2\u3002<\/p>\n\n\n\n
              \u793a\u4f8b<\/strong><\/h4>\n\n\n\n
              \u5728 orders<\/code> \u96c6\u5408\u4e2d\u67e5\u8be2 users<\/code> \u8868\u7684\u7528\u6237\u4fe1\u606f\uff1a<\/p>\n\n\n\n
              db.orders.aggregate([\n  {\n    $lookup: {\n      from: \"users\",       \/\/ \u5173\u8054\u96c6\u5408\n      localField: \"userId\", \/\/ \u5f53\u524d\u96c6\u5408\u7684\u5b57\u6bb5\n      foreignField: \"_id\",  \/\/ \u76ee\u6807\u96c6\u5408\u7684\u5b57\u6bb5\n      as: \"userInfo\"       \/\/ \u5173\u8054\u6570\u636e\u7684\u5b57\u6bb5\u540d\n    }\n  }\n])<\/code><\/pre>\n\n\n\n
              \u7b49\u4ef7\u4e8e SQL\uff1a<\/p>\n\n\n\n
              SELECT orders.*, users.*\nFROM orders\nJOIN users ON orders.userId = users._id;<\/code><\/pre>\n\n\n\n
              \n\n\n\n
              10. \u7edf\u8ba1\u6587\u6863\u6570\uff08$count\uff09<\/strong><\/h3>\n\n\n\n
              \u7edf\u8ba1 status=\"active\"<\/code> \u7684\u5546\u54c1\u6570\uff1a<\/p>\n\n\n\n
              db.products.aggregate([\n  { $match: { status: \"active\" } },\n  { $count: \"totalActiveProducts\" }\n])<\/code><\/pre>\n\n\n\n
              \n\n\n\n
              \u603b\u7ed3<\/strong><\/h3>\n\n\n\n
              \u64cd\u4f5c<\/strong><\/th>MongoDB \u805a\u5408<\/strong><\/th>SQL \u5bf9\u5e94<\/strong><\/th><\/tr><\/thead>
              \u8fc7\u6ee4<\/td>$match<\/code><\/td>WHERE<\/code><\/td><\/tr>
              \u5206\u7ec4<\/td>$group<\/code><\/td>GROUP BY<\/code><\/td><\/tr>
              \u8ba1\u7b97<\/td>$sum<\/code>, $avg<\/code>, $max<\/code><\/td>SUM()<\/code>, AVG()<\/code>, MAX()<\/code><\/td><\/tr>
              \u6392\u5e8f<\/td>$sort<\/code><\/td>ORDER BY<\/code><\/td><\/tr>
              \u9650\u5236\u8fd4\u56de<\/td>$limit<\/code><\/td>LIMIT<\/code><\/td><\/tr>
              \u8df3\u8fc7<\/td>$skip<\/code><\/td>OFFSET<\/code><\/td><\/tr>
              \u9009\u62e9\u5b57\u6bb5<\/td>$project<\/code><\/td>SELECT<\/code><\/td><\/tr>
              \u62c6\u5206\u6570\u7ec4<\/td>$unwind<\/code><\/td>\u65e0\u76f4\u63a5\u5bf9\u5e94<\/strong><\/td><\/tr>
              \u5173\u8054\u67e5\u8be2<\/td>$lookup<\/code><\/td>JOIN<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
              \n\n\n\n
              MongoDB \u805a\u5408<\/strong> \u662f\u5f3a\u5927\u7684\u6570\u636e\u5904\u7406\u5de5\u5177\uff0c\u53ef\u4ee5\u5b9e\u73b0\u590d\u6742\u7684\u6570\u636e\u5206\u6790\uff01\u66f4\u591a\u8be6\u7ec6\u5185\u5bb9\u8bf7\u5173\u6ce8\u5176\u4ed6\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
              MongoDB \u805a\u5408\uff08Aggregation\uff09 \u901a\u8fc7 aggregate() \u65b9\u6cd5\u5bf9\u6587\u6863\u8fdb\u884c\u590d\u6742\u7684\u6570\u636e\u5904\u7406\uff0c\u5982 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[77],"tags":[],"class_list":["post-2457","post","type-post","status-publish","format-standard","hentry","category-mongodb"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2457","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/comments?post=2457"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2457\/revisions"}],"predecessor-version":[{"id":2458,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2457\/revisions\/2458"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=2457"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=2457"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=2457"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}