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法律研究MongoDB 中 SQL “like” 的等價物是什麼？
可以使用 “$regex” 運算子來實現 MongoDB 中與 SQL ‘like’ 等效的功能。要實現它，請使用文件建立集合。使用文件建立集合的查詢如下所示 −
> db.sqlLikeDemo.insertOne({"UserName":"John Smith","UserAge":24});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c912e124afe5c1d2279d6a5")
}
> db.sqlLikeDemo.insertOne({"UserName":"John Doe","UserAge":21});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c912e264afe5c1d2279d6a6")
}
> db.sqlLikeDemo.insertOne({"UserName":"Chris Williams","UserAge":22});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c912e404afe5c1d2279d6a7")
}
> db.sqlLikeDemo.insertOne({"UserName":"Robert Taylor","UserAge":26});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c912e4d4afe5c1d2279d6a8")
}
> db.sqlLikeDemo.insertOne({"UserName":"John Brown","UserAge":27});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c912e6c4afe5c1d2279d6a9")
}
> db.sqlLikeDemo.insertOne({"UserName":"Mike Brown","UserAge":23});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c912e794afe5c1d2279d6aa")
}
> db.sqlLikeDemo.insertOne({"UserName":"Larry Smith","UserAge":24});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c912e8c4afe5c1d2279d6ab")
}使用 find() 方法從集合顯示所有文件。查詢如下所示 −
> db.sqlLikeDemo.find().pretty();
輸出如下 −
{
"_id" : ObjectId("5c912e124afe5c1d2279d6a5"),
"UserName" : "John Smith",
"UserAge" : 24
}
{
"_id" : ObjectId("5c912e264afe5c1d2279d6a6"),
"UserName" : "John Doe",
"UserAge" : 21
}
{
"_id" : ObjectId("5c912e404afe5c1d2279d6a7"),
"UserName" : "Chris Williams",
"UserAge" : 22
}
{
"_id" : ObjectId("5c912e4d4afe5c1d2279d6a8"),
"UserName" : "Robert Taylor",
"UserAge" : 26
}
{
"_id" : ObjectId("5c912e6c4afe5c1d2279d6a9"),
"UserName" : "John Brown",
"UserAge" : 27
}
{
"_id" : ObjectId("5c912e794afe5c1d2279d6aa"),
"UserName" : "Mike Brown",
"UserAge" : 23
}
{
"_id" : ObjectId("5c912e8c4afe5c1d2279d6ab"),
"UserName" : "Larry Smith",
"UserAge" : 24
}查詢工作方式如下 SQL ‘like’ 子句，即帶有 “UserName” John 的記錄 −
> db.sqlLikeDemo.find({"UserName":{"$regex": "John"}}).pretty();輸出如下 −
{
"_id" : ObjectId("5c912e124afe5c1d2279d6a5"),
"UserName" : "John Smith",
"UserAge" : 24
}
{
"_id" : ObjectId("5c912e264afe5c1d2279d6a6"),
"UserName" : "John Doe",
"UserAge" : 21
}
{
"_id" : ObjectId("5c912e6c4afe5c1d2279d6a9"),
"UserName" : "John Brown",
"UserAge" : 27
}
更新於: 30-Jul-2019
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