Mongodb 3.2 SQL对应聚合 官方

本文介绍如何将常见的SQL聚合操作转换为MongoDB的聚合管道操作,包括使用$match、$group、$project等操作符实现WHERE、GROUP BY、SELECT等功能。

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SQL to Aggregation Mapping Chart

The aggregation pipeline allowsMongoDB to provide native aggregation capabilities that corresponds tomany common data aggregation operations in SQL.

The following table provides an overview of common SQL aggregationterms, functions, and concepts and the corresponding MongoDBaggregation operators:

SQL Terms, Functions, and ConceptsMongoDB Aggregation Operators
WHERE$match
GROUP BY$group
HAVING$match
SELECT$project
ORDER BY$sort
LIMIT$limit
SUM()$sum
COUNT()$sum
join

$lookup

New in version 3.2.

Examples

The following table presents a quick reference of SQL aggregationstatements and the corresponding MongoDB statements. The examples inthe table assume the following conditions:

  • The SQL examples assume two tables, orders andorder_lineitem that join by theorder_lineitem.order_id andtheorders.id columns.

  • The MongoDB examples assume one collection orders that containdocuments of the following prototype:

    {
      cust_id: "abc123",
      ord_date: ISODate("2012-11-02T17:04:11.102Z"),
      status: 'A',
      price: 50,
      items: [ { sku: "xxx", qty: 25, price: 1 },
               { sku: "yyy", qty: 25, price: 1 } ]
    }
    
SQL ExampleMongoDB ExampleDescription
SELECT COUNT(*) AS count
FROM orders
db.orders.aggregate( [
   {
     $group: {
        _id: null,
        count: { $sum: 1 }
     }
   }
] )
Count all recordsfrom orders
SELECT SUM(price) AS total
FROM orders
db.orders.aggregate( [
   {
     $group: {
        _id: null,
        total: { $sum: "$price" }
     }
   }
] )
Sum the price fieldfromorders
SELECT cust_id,
       SUM(price) AS total
FROM orders
GROUP BY cust_id
db.orders.aggregate( [
   {
     $group: {
        _id: "$cust_id",
        total: { $sum: "$price" }
     }
   }
] )
For each unique cust_id,sum theprice field.
SELECT cust_id,
       SUM(price) AS total
FROM orders
GROUP BY cust_id
ORDER BY total
db.orders.aggregate( [
   {
     $group: {
        _id: "$cust_id",
        total: { $sum: "$price" }
     }
   },
   { $sort: { total: 1 } }
] )
For each unique cust_id,sum theprice field,results sorted by sum.
SELECT cust_id,
       ord_date,
       SUM(price) AS total
FROM orders
GROUP BY cust_id,
         ord_date
db.orders.aggregate( [
   {
     $group: {
        _id: {
           cust_id: "$cust_id",
           ord_date: {
               month: { $month: "$ord_date" },
               day: { $dayOfMonth: "$ord_date" },
               year: { $year: "$ord_date"}
           }
        },
        total: { $sum: "$price" }
     }
   }
] )
For each uniquecust_id,ord_date grouping,sum theprice field.Excludes the time portion of the date.
SELECT cust_id,
       count(*)
FROM orders
GROUP BY cust_id
HAVING count(*) > 1
db.orders.aggregate( [
   {
     $group: {
        _id: "$cust_id",
        count: { $sum: 1 }
     }
   },
   { $match: { count: { $gt: 1 } } }
] )
For cust_id with multiple records,return thecust_id andthe corresponding record count.
SELECT cust_id,
       ord_date,
       SUM(price) AS total
FROM orders
GROUP BY cust_id,
         ord_date
HAVING total > 250
db.orders.aggregate( [
   {
     $group: {
        _id: {
           cust_id: "$cust_id",
           ord_date: {
               month: { $month: "$ord_date" },
               day: { $dayOfMonth: "$ord_date" },
               year: { $year: "$ord_date"}
           }
        },
        total: { $sum: "$price" }
     }
   },
   { $match: { total: { $gt: 250 } } }
] )
For each unique cust_id,ord_dategrouping, sum theprice fieldand return only where thesum is greater than 250.Excludes the time portion of the date.
SELECT cust_id,
       SUM(price) as total
FROM orders
WHERE status = 'A'
GROUP BY cust_id
db.orders.aggregate( [
   { $match: { status: 'A' } },
   {
     $group: {
        _id: "$cust_id",
        total: { $sum: "$price" }
     }
   }
] )
For each unique cust_idwith statusA,sum the price field.
SELECT cust_id,
       SUM(price) as total
FROM orders
WHERE status = 'A'
GROUP BY cust_id
HAVING total > 250
db.orders.aggregate( [
   { $match: { status: 'A' } },
   {
     $group: {
        _id: "$cust_id",
        total: { $sum: "$price" }
     }
   },
   { $match: { total: { $gt: 250 } } }
] )
For each unique cust_idwith statusA,sum the price field and returnonly where thesum is greater than 250.
SELECT cust_id,
       SUM(li.qty) as qty
FROM orders o,
     order_lineitem li
WHERE li.order_id = o.id
GROUP BY cust_id
db.orders.aggregate( [
   { $unwind: "$items" },
   {
     $group: {
        _id: "$cust_id",
        qty: { $sum: "$items.qty" }
     }
   }
] )
For each unique cust_id,sum the correspondingline itemqty fieldsassociated with theorders.
SELECT COUNT(*)
FROM (SELECT cust_id,
             ord_date
      FROM orders
      GROUP BY cust_id,
               ord_date)
      as DerivedTable
db.orders.aggregate( [
   {
     $group: {
        _id: {
           cust_id: "$cust_id",
           ord_date: {
               month: { $month: "$ord_date" },
               day: { $dayOfMonth: "$ord_date" },
               year: { $year: "$ord_date"}
           }
        }
     }
   },
   {
     $group: {
        _id: null,
        count: { $sum: 1 }
     }
   }
] )
Count the number of distinctcust_id,ord_date groupings.Excludes the time portion of the date.

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