可以在$ regex中使用MongoDB字段值作为模式吗？
是的，为此，请使用$indexOfCP运算符以及聚合框架。首先让我们创建一个包含文档的集合-
> db.patterDemo.insertOne(
{
"ClientName": "John", "ClientWebsiteName":"webbuziness.com/John/business"
}
);
{
"acknowledged" : true,
"insertedId" : ObjectId("5cea40acef71edecf6a1f68d")
}
> db.patterDemo.insertOne(
{
"ClientName": "Carol", "ClientWebsiteName":"solvecoding.com/business"
}
);
{
"acknowledged" : true,
"insertedId" : ObjectId("5cea40acef71edecf6a1f68e")
}以下是在find()方法的帮助下显示集合中所有文档的查询-
> db.patterDemo.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5cea40acef71edecf6a1f68d"),
"ClientName" : "John",
"ClientWebsiteName" : "abcd.com"
}
{
"_id" : ObjectId("5cea40acef71edecf6a1f68e"),
"ClientName" : "Carol",
"ClientWebsiteName" : "pqrs.com"
}以下是将字段值用作$regex中的模式的查询-
> db.patterDemo.aggregate([ { "$match": { "$expr": { "$ne": [ { "$indexOfCP": ["$ClientWebsiteName", "$ClientName"] }, -1 ] } }} ]);这将产生以下输出-
{ "_id" : ObjectId("5cea40acef71edecf6a1f68d"), "ClientName" : "John", "ClientWebsiteName" : "abcd.com" }