MongoDB查询将带逗号的字符串转换为双精度
对于此类转换，请使用aggregate()。让我们创建一个包含文档的集合-
> db.demo335.insertOne({"Value":"45,67,78.0"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e522a1cf8647eb59e562091")
}
> db.demo335.insertOne({"Value":"17664,76,534.0"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e522a26f8647eb59e562092")
}
> db.demo335.insertOne({"Value":"8899,322,135,875.50"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e522a34f8647eb59e562093")
}
> db.demo335.insertOne({"Value":"1,533.07"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e522ab9f8647eb59e562094")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo335.find();
这将产生以下输出-
{ "_id" : ObjectId("5e522a1cf8647eb59e562091"), "Value" : "45,67,78.0" }
{ "_id" : ObjectId("5e522a26f8647eb59e562092"), "Value" : "17664,76,534.0" }
{ "_id" : ObjectId("5e522a34f8647eb59e562093"), "Value" : "8899,322,135,875.50" }
{ "_id" : ObjectId("5e522ab9f8647eb59e562094"), "Value" : "1,533.07" }以下是将带逗号的字符串转换为double的查询-
db.demo335.aggregate([
... { $project: {
... data: {
... $convert: {
... input: {
... $reduce: {
... input: {
... $split: ['$Value', ',']
... },
... initialValue: '',
... in: {
... $concat: ['$$value', '$$this']
... }
... }
... },
... to: 'double',
... onError: 0
... }
... }
... }}
... ])这将产生以下输出-
{ "_id" : ObjectId("5e522a1cf8647eb59e562091"), "data" : 456778 }
{ "_id" : ObjectId("5e522a26f8647eb59e562092"), "data" : 1766476534 }
{ "_id" : ObjectId("5e522a34f8647eb59e562093"), "data" : 8899322135875.5 }
{ "_id" : ObjectId("5e522ab9f8647eb59e562094"), "data" : 1533.07 }