$addFields 中的日期计算
date calculations in $addFields
我想在聚合管道的 $addFields 阶段执行日期计算。这适用于硬编码乘法器,但如果我尝试从文档传递值,则会失败。
MongoDB版本是Atlas 4.0.6。
鉴于此文档结构:
{
"_id" : ObjectId("5c9e78c61c9d440000a83cca"),
"title" : "InterventionA",
"thresholdCount" : 4,
"thresholdUnit" : "weeks"
},
{
"_id" : ObjectId("5c9e7d361c9d440000a83ccb"),
"title" : "InterventionB",
"thresholdCount" : 4,
"thresholdUnit" : "days"
}
..此查询有效。请注意 (*4) 中的乘数 $cond 是硬编码的。
const endDate = new Date();
endDate.setHours(0, 0, 0, 0);
const ms1d = 24 * 60 * 60 * 1000; /* milliseconds per day */
const ms1w = 7 * ms1d; /* milliseconds per week */
db.stackex.aggregate([
{
$addFields: {
dateRange: {
$cond: {
if: { $eq: ["$thresholdUnit", "weeks"] },
then: { "start": { $subtract: [endDate, ms1w * 4] }, "end": endDate},
else: { "start": { $subtract: [endDate, ms1d * 4] }, "end": endDate}
}
}
}
}
]);
期望的结果是:
{
"_id" : ObjectId("5c9e78c61c9d440000a83cca"),
"title" : "InterventionA",
"thresholdCount" : 4,
"thresholdUnit" : "weeks",
"dateRange" : {
"start" : ISODate("2019-02-28T23:00:00.000-08:00"),
"end" : ISODate("2019-03-29T00:00:00.000-07:00")
}
},
{
"_id" : ObjectId("5c9e7d361c9d440000a83ccb"),
"title" : "InterventionB",
"thresholdCount" : 4,
"thresholdUnit" : "days",
"dateRange" : {
"start" : ISODate("2019-03-25T00:00:00.000-07:00"),
"end" : ISODate("2019-03-29T00:00:00.000-07:00")
}
}
我想将每个文档的硬编码 (* 4) 替换为 $thresholdCount
的值。我的语法不对。
下面的代码因 "message" 失败:"Cannot negate the minimum duration"
const endDate = new Date();
endDate.setHours(0, 0, 0, 0);
const ms1d = 24 * 60 * 60 * 1000; /* milliseconds per day */
const ms1w = 7 * ms1d; /* milliseconds per week */
db.stackex.aggregate([
{
$addFields: {
dateRange: {
$cond: {
if: { $eq: ["$thresholdUnit", "weeks"] },
then: { "start": { $subtract: [endDate, ms1w * "$thresholdCount"] }, "end": endDate},
else: { "start": { $subtract: [endDate, ms1d * "$thresholdCount"] }, "end": endDate}
}
}
}
}
]);
您需要使用$multiply
运算符进行乘法计算。
所以用{ $multiply: [ms1w, "$thresholdCount"] }
替换ms1w * "$thresholdCount"
这里是完整的 $cond
表达式:
$cond: {
if: { $eq: ["$thresholdUnit", "weeks"] },
then: { "start": { $subtract: [endDate, { $multiply: [ms1w, "$thresholdCount"] } ] }, "end": endDate},
else: { "start": { $subtract: [endDate, { $multiply: [ms1d, "$thresholdCount"] } ] }, "end": endDate}
}
我想在聚合管道的 $addFields 阶段执行日期计算。这适用于硬编码乘法器,但如果我尝试从文档传递值,则会失败。
MongoDB版本是Atlas 4.0.6。
鉴于此文档结构:
{
"_id" : ObjectId("5c9e78c61c9d440000a83cca"),
"title" : "InterventionA",
"thresholdCount" : 4,
"thresholdUnit" : "weeks"
},
{
"_id" : ObjectId("5c9e7d361c9d440000a83ccb"),
"title" : "InterventionB",
"thresholdCount" : 4,
"thresholdUnit" : "days"
}
..此查询有效。请注意 (*4) 中的乘数 $cond 是硬编码的。
const endDate = new Date();
endDate.setHours(0, 0, 0, 0);
const ms1d = 24 * 60 * 60 * 1000; /* milliseconds per day */
const ms1w = 7 * ms1d; /* milliseconds per week */
db.stackex.aggregate([
{
$addFields: {
dateRange: {
$cond: {
if: { $eq: ["$thresholdUnit", "weeks"] },
then: { "start": { $subtract: [endDate, ms1w * 4] }, "end": endDate},
else: { "start": { $subtract: [endDate, ms1d * 4] }, "end": endDate}
}
}
}
}
]);
期望的结果是:
{
"_id" : ObjectId("5c9e78c61c9d440000a83cca"),
"title" : "InterventionA",
"thresholdCount" : 4,
"thresholdUnit" : "weeks",
"dateRange" : {
"start" : ISODate("2019-02-28T23:00:00.000-08:00"),
"end" : ISODate("2019-03-29T00:00:00.000-07:00")
}
},
{
"_id" : ObjectId("5c9e7d361c9d440000a83ccb"),
"title" : "InterventionB",
"thresholdCount" : 4,
"thresholdUnit" : "days",
"dateRange" : {
"start" : ISODate("2019-03-25T00:00:00.000-07:00"),
"end" : ISODate("2019-03-29T00:00:00.000-07:00")
}
}
我想将每个文档的硬编码 (* 4) 替换为 $thresholdCount
的值。我的语法不对。
下面的代码因 "message" 失败:"Cannot negate the minimum duration"
const endDate = new Date();
endDate.setHours(0, 0, 0, 0);
const ms1d = 24 * 60 * 60 * 1000; /* milliseconds per day */
const ms1w = 7 * ms1d; /* milliseconds per week */
db.stackex.aggregate([
{
$addFields: {
dateRange: {
$cond: {
if: { $eq: ["$thresholdUnit", "weeks"] },
then: { "start": { $subtract: [endDate, ms1w * "$thresholdCount"] }, "end": endDate},
else: { "start": { $subtract: [endDate, ms1d * "$thresholdCount"] }, "end": endDate}
}
}
}
}
]);
您需要使用$multiply
运算符进行乘法计算。
所以用{ $multiply: [ms1w, "$thresholdCount"] }
ms1w * "$thresholdCount"
这里是完整的 $cond
表达式:
$cond: {
if: { $eq: ["$thresholdUnit", "weeks"] },
then: { "start": { $subtract: [endDate, { $multiply: [ms1w, "$thresholdCount"] } ] }, "end": endDate},
else: { "start": { $subtract: [endDate, { $multiply: [ms1d, "$thresholdCount"] } ] }, "end": endDate}
}