The find(SearchConditionStr) 函数用于搜索集合中的文档，类似于 SQL 数据库的 SELECT 语句。它使用搜索条件字符串 (SearchConditionStr) 作为参数，以指定应从数据库中返回的文档。The execute() 函数触发 find() 操作的实际执行。

The SearchConditionStr 可以采用以下几种形式

可以将 fields()、sort() 和 limit() 等多种方法链接到 find() 函数，以进一步细化结果。例如

myColl.find("Name LIKE 'Austra%'").fields("Code")
myColl.find("geography.Continent LIKE 'A%'").limit(10)

也支持使用 bind() 进行参数绑定。以下示例说明了 bind() 与 find() 的用法

MySQL Shell JavaScript 代码

// Use the collection 'my_collection'
var myColl = db.getCollection('my_collection');

// Find a single document that has a field 'name' that starts with 'L'
var docs = myColl.find('name like :param').
            limit(1).bind('param', 'L%').execute();

print(docs.fetchOne());

// Get all documents with a field 'name' that starts with 'L'
docs = myColl.find('name like :param').
        bind('param','L%').execute();

var myDoc;
while (myDoc = docs.fetchOne()) {
  print(myDoc);
}

MySQL Shell Python 代码

# Use the collection 'my_collection'
myColl = db.get_collection('my_collection')

# Find a single document that has a field 'name' that starts with 'L'
docs = myColl.find('name like :param').limit(1).bind('param', 'L%').execute()

print(docs.fetch_one())

# Get all documents with a field 'name' that starts with 'L'
docs = myColl.find('name like :param').bind('param','L%').execute()

myDoc = docs.fetch_one()
while myDoc:
  print(myDoc)
  myDoc = docs.fetch_one()

Node.js JavaScript 代码

// Use the collection 'my_collection'
var myColl = db.getCollection('my_collection');

// Find a single document that has a field 'name' that starts with 'L'
myColl
  .find('name like :name')
  .bind('name', 'L%')
  .limit(1)
  .execute(function (doc) {
    console.log(doc);
  })
  .then(function () {
    // handle details
  });

// Get all documents with a field 'name' that starts with 'L'
myColl
  .find('name like :name')
  .bind('name', 'L%')
  .execute(function (doc) {
    console.log(doc);
  })
  .then(function () {
    // handle details
  });

C# 代码

// Use the collection "my_collection"
var myColl = db.GetCollection("my_collection");

// Find a single document that has a field "name" that starts with "L"
var docs = myColl.Find("name like :param")
.Limit(1).Bind("param", "L%").Execute();

Console.WriteLine(docs.FetchOne());

// Get all documents with a field "name" that starts with "L"
docs = myColl.Find("name like :param")
.Bind("param", "L%").Execute();

while (docs.Next())
{
    Console.WriteLine(docs.Current);
}

Python 代码

# Use the collection 'my_collection'
my_coll = my_schema.get_collection('my_collection')

# Find a single document that has a field 'name' that starts with 'L'
docs = my_coll.find('name like :param').limit(1).bind('param', 'L%').execute()

print(docs.fetch_one())

# Get all documents with a field 'name' that starts with 'L'
docs = my_coll.find('name like :param').bind('param', 'L%').execute()

doc = docs.fetch_one()
print(doc)

Java 代码

// Use the collection 'my_collection'
Collection myColl = db.getCollection("my_collection");

// Find a single document that has a field 'name' that starts with 'L'
DocResult docs = myColl.find("name like :name").bind("name", "L%").execute();

System.out.println(docs.fetchOne());

// Get all documents with a field 'name' that starts with 'L'
docs = myColl.find("name like :name").bind("name", "L%").execute();

while (docs.hasNext()) {
    DbDoc myDoc = docs.next();
    System.out.println(myDoc);
}

C++ 代码

// Use the collection 'my_collection'
Collection myColl = db.getCollection("my_collection");

// Find a single document that has a field 'name' that starts with 'L'
DocResult docs = myColl.find("name like :param")
                       .limit(1).bind("param", "L%").execute();

cout << docs.fetchOne() << endl;

// Get all documents with a field 'name' that starts with 'L'
docs = myColl.find("name like :param")
             .bind("param","L%").execute();

DbDoc myDoc;
while ((myDoc = docs.fetchOne()))
{
  cout << myDoc << endl;
}

有关 find() 在 EBNF 中语法的详细信息，请参阅 CollectionFindFunction。