mongodb聚合查询aggregation pipeline示例

布满荆棘的人生 2022-02-01 06:09 345阅读 0赞

参考来源，[mongodb官网文档][mongodb]  
**示例说明**  
我们以2019第一季度基金重仓股票数据为例，查询2019基金重仓股票排行

数据截图  
![数据结构图][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDI5NDMzMg_size_16_color_FFFFFF_t_70]  
**聚合语句**

db.fund_stock.aggregate([
        {
            $match: {  
                currentYear: "2019"
            }
        },
        {
            $group: {    
                _id: "$stockCode",     
    			stockName:{$first:"$stockName"},
                num_tutorial: { 
                    $sum: 1
                },
    			currentYear:{$first:"$currentYear"},
    			fundCodes:{$push:"$fundCode"}
            }
        },
        {
            $sort: {
                num_tutorial: -1
            }
        },
    		{
    			$project:{
    			   _id:false,
    				 stockCode:"$_id",
    				 stockName: "$stockName",
    				 coun:"$num_tutorial",
    				  currentYear:"$currentYear",
    				 fundCodes:"$fundCodes"
    			}
    		}
    ])

**输出结果**

![结果示例][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDI5NDMzMg_size_16_color_FFFFFF_t_70 1]

[mongodb]: https://docs.mongodb.com/v3.6/aggregation/
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDI5NDMzMg_size_16_color_FFFFFF_t_70]: /images/20220201/b3521c1292b44e1488dcb655b51e790b.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDI5NDMzMg_size_16_color_FFFFFF_t_70 1]: /images/20220201/0b29f0336e614a1fb7b7fbf95f79e8dc.png