1、单一字段分组
分组后不会展示其他字段, _id为固定写法，userid为分组字段
1 2 | # 比如对比sql：select userid from testgroup by useriddb.test.aggregate({"$group":{"_id":"$userid"}} ) |
效果：
2、多字段分组
_id为固定写法，userid与articleid为分组字段，多字段时需要设置一个别名
1 2 | # 比如对比sql：select userid,articleid from testgroup by userid,articleiddb.test.aggregate({"$group":{"_id":{"userid":"$userid","articleid":"$articleid"}}}) |
效果：
3、条件匹配分组
$match表示匹配条件，在group前表示where，在后表示having，userid为分组字段
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | # 比如对比sql：select userid from testwhere userid in("1","2") group by useriddb.test.aggregate( {"$match":{"userid":{"$in":["1","2"]}}}, {"$group":{"_id":"$userid"}})或者# 比如对比sql：select userid,articleid from test where userid in("1","2") group by useriddb.test.aggregate( {"$match":{"userid":{"$in":["1","2"]}}}, {"$group":{"_id":{"userid":"$userid","articleid":"$articleid"}}})或者having聚合查询# 比如：select userid,avg(price) as avg from test where userid >'10' group by userid having avg>35db.test.aggregate( {"$match":{"userid":{"$gt":"10"}}}, {"$group":{"_id":"$userid",'avg':{"$avg":"$price"}}}, {"$match":{"avg":{"$gt":35}}}) |
效果：
4、分组分页排序
限制：$limit、跳过：$skip
1 2 3 4 5 | db.test.aggregate( {"$group":{"_id":"$userid"}}, {"$skip":1}, {"$limit":2} ) |
5、聚合分组
聚合分组,分为：$sum、$avg、$max、$min、$first、$last，聚合结果需要使用别名，并且可以结合条件和排序等元素
为了测试聚合，增加一下文件：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | db.test.insert([{ "articleid":"1", "price":200, "userid":"5"},{ "articleid":"2", "price":300, "userid":"5"},{ "articleid":"3", "price":400, "userid":"5"},{ "articleid":"1", "price":200, "userid":"6"},{ "articleid":"2", "price":300, "userid":"7"}]); |
5.1、sum聚合-求数值总和
求某个数值总和，userid分组字段[可以用于多字段聚合],{“$sum”:$price}表示求price合计
1 | db.test.aggregate({"$group":{"_id":"$userid","total":{"$sum":"$price"}}}) |
5.2、sum聚合-求分组后数量
1 | db.test.aggregate({"$group":{"_id":"$userid","total":{"$sum":1}}}) |
效果：
5.3、avg、max、min聚合
avg、max、min可以分开使用，也可以一起使用
1 | db.test.aggregate({"$group":{"_id":"$userid","avg":{"$avg":"$price"},"max":{"$max":"$price"},"min":{"$min":"$price"}}}) |
效果：
5.4、复合聚合
可以多字段聚合求值，通过sum与avg、max、min进行组合
1 2 3 | db.test.aggregate({"$group":{"_id":"$userid" ,"total":{"$sum":"$price"} ,"avg":{"$avg":"$price"}}}) |
效果：
5.5、聚合分组排序
对聚合结果进行排序，$sort-排序，avg-聚合结果的别名，1：升序，-1：降序
1 2 3 4 5 | # 先按userid降序,再avg升序 db.test.aggregate({"$group":{"_id":"$userid" ,"avg":{"$avg":"$price"}}} ,{"$sort":{"avg":1}} ,{"$sort":{"_id":-1}}) |
效果：
5.6、首尾取值聚合
$first-第一个元素、$last-最后一个元素
1 | vdb.test.aggregate({"$group":{"_id":"$userid","prices":{"$first":"$price"}}}) |
效果：
5.7、聚合分组拼接
等同于group_concat，$push-元素可重复，$addToSet-元素不可重复，将分组后的数据拼接为一个数组
1 | db.test.aggregate({"$group":{"_id":"$userid","names":{"$push":"$price"}}}) |
效果：
补充：关于MongoDB中一些复杂的聚合分组查询操作
一、字段切割&条件判断
汇总各个店铺【$shop_name】在某个时间段【$patrol_time】内违规【$whether_violates == ‘Y’】的记录数
1.$substr:[‘字段名’,开始下标,结束下标]
2.$cond:{if…then…else}
查询SQL如下：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 | db.t_tbshop_patrol.aggregate([ { "$project": { "yearMonthDay": { "$substr": ["$patrol_time", 0, 10] }, "patrol_time": 1, "shop_name": 1, "whether_violates": 1, "y_count": { "$sum": { "$cond": { "if": { "$eq": ["$whether_violates", "Y"] }, "then": 1, "else": 0 } } } } }, { "$match": { "patrol_time": { "$gte": "2021-09-29 00:00:00", "$lte": "2021-09-29 23:59:59" } } }, { "$group": { "_id": { "patrol_time": "$yearMonthDay", "shop_name": "$shop_name" }, "violate_y": { "$sum": "$y_count" } } }, /* 只展示汇总结果大于0的店铺数据，去掉下面{'$match'}则展示所有店铺数据 */ { "$match": { "violate_y": { "$gt": 0 } } }]) |
查询结果如下：
/* 1 */
{
“_id” : {
“patrol_time” : “2021-09-29”,
“shop_name” : “VETA个护海外旗舰店”
},
“violate_y” : 5.0
}/* 2 */
{
“_id” : {
“patrol_time” : “2021-09-29”,
“shop_name” : “swisseFuJun海外专卖店”
},
“violate_y” : 24.0
}/* 3 */
{
“_id” : {
“patrol_time” : “2021-09-29”,
“shop_name” : “咿儿润旗舰店”
},
“violate_y” : 1.0
}
二、联表查询&类型转换&拆分数组
根据日期查询订单表中每条订单数据每种商品（非赠品）的总金额（业务需要显示仓库，但原始数据中只有仓库编号，所以和仓库信息表【t_warehouse_info】使用联表查询）
1.$lookup
2.$toDouble、$convert
3.$unwind
原始数据示例：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 | { "_id" : ObjectId("5f33abcdfc12b1f2d21b2e5d"), /* 订单编号 */ "order_sn" : "12023232223920", "add_time" : "2021-09-29 20:01:25", "complete_time" : "1596330674", /* 仓库编号 */ "fhck" : "151", "last_update" : "2021-09-29 09:14:03", "lylx" : "1", /* 订单商品明细：同一笔订单下的同一商品可能有多条，所以需要根据商品编号【goods_sn】分组求和 */ "orderDetailGets" : [ { "goods_sn" : "6925425422173", "goods_id" : "2518", "goods_number" : "3", "goods_price" : "35.19", "shop_price" : "79.00", "share_price" : "35.19", /* 支付金额 */ "share_payment" : "35.19", "original_order_sn" : "12023232223920", "goods_name" : "口力橡皮糖500g", /* 是否赠品（1：是；0：否）*/ "is_gift" : "0", "share_shipping_fee" : "0.00" }, { "goods_sn" : "6971083865227", "goods_id" : "1569", "goods_number" : "1", "goods_price" : "1.87", "shop_price" : "4.50", "share_price" : "1.87", "share_payment" : "1.87", "original_order_sn" : "12023232223920", "goods_name" : "口力组合橡皮糖随手包30g", "is_gift" : "0", "share_shipping_fee" : "0.00" }, { "goods_sn" : "6971083865227", "goods_id" : "1569", "sku_id" : "1569", "goods_number" : "2", "goods_price" : "1.87", "shop_price" : "4.50", "goods_price" : "1.87", "share_payment" : "3.74", "original_order_sn" : "12023232223920", "goods_name" : "口力组合橡皮糖随手包30g", "is_gift" : "0", "share_shipping_fee" : "0.00" } ], "order_msg" : "", "order_status" : "5", "pay_time" : "2021-09-29 20:03:13", "payment" : "37.06", "sd_name" : "口力旗舰店", "total_amount" : "84.54", "weigh" : "0.800000"} |
查询SQL如下：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 | db.getCollection('t_shop_order').aggregate([ { "$match": { "add_time": { "$gte": "2021-12-14 00:00:00", "$lte": "2021-12-14 23:59:59" } } }, /* $lookup联表查询：相当于left join；关联后的子表数据无论是1对1还是1对多，都会形成一个数组对象 */ { "$lookup": { "from": "t_warehouse_info", /* 主表的关联字段名 */ "localField": "fhck", /* 关联表的字段名 */ "foreignField": "ckdm", /* 关联表别名，作为数据的字段名 */ "as": "warehouse_info" } }, /* $unwind拆分数组对象，扁平化展示 */ { "$unwind": "$orderDetailGets" }, { "$project": { "order_sn": 1, "add_time": 1, "goods_sn": "$orderDetailGets.goods_sn", "is_gift": "$orderDetailGets.is_gift", /* $convert类型转换：将字符串转换为int类型，以助于后面的数据统计 */ "goods_number": { "$convert": { "input": "$orderDetailGets.goods_number", "to": "int" } }, "goods_name": "$orderDetailGets.goods_name", /* $ifNull空判断：如果对应字符串为null，则设置默认值为0 */ /* $toDouble转换为浮点型：将数据转换为浮点型数据 */ "share_payment": { "$ifNull": [{ "$toDouble": "$orderDetailGets.share_payment" }, 0] }, "ckmc": "$warehouse_info.ckmc" } }, { "$match": { "is_gift": "0" } }, { "$unwind": "$ckmc" }, { "$group": { _id: { "order_sn": "$order_sn", "add_time": "$add_time", "goods_sn": "$goods_sn", "goods_name": "$goods_name" }, "goods_number": { "$sum": "$goods_number" }, "share_payment": { "$sum": "$share_payment" } } }]) |
查询SQL如下：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | /* 1 */{ "_id" : { "order_sn" : "12023232223920", "add_time" : "2021-12-14 12:22:16", "goods_sn" : "6925425422173", "goods_name" : "口力橡皮糖500g" }, "goods_number" : 3, "share_payment" : 35.19}/* 2 */{ "_id" : { "order_sn" : "12023232223920", "add_time" : "2021-12-14 22:37:09", "goods_sn" : "6971083865227", "goods_name" : "口力组合橡皮糖随手包30g" }, "goods_number" : 3, "share_payment" : 5.61} |
总结
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