CollectionFind::fields

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CollectionFind::fields — Set document field filter

说明

public mysql_xdevapi\CollectionFind::fields ( string $projection ) : mysql_xdevapi\CollectionFind

Defined the columns for the query to return. If not defined then all columns are used.

参数

projection: Can either be a single string or an array of string, those strings are identifying the columns that have to be returned for each document that match the search condition.

返回值

A CollectionFind object that can be used for further processing.

范例

Example #1 mysql_xdevapi\CollectionFind::fields() example


<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");

$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();

$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");

$create
  ->add('{"name": "Alfred", "age": 18, "job": "Butler"}')
  ->execute();

// ...

$collection = $schema->getCollection("people");

$result = $collection
  ->find('job like :job and age > :age')
  ->bind(['job' => 'Butler', 'age' => 16])
  ->fields('name')
  ->execute();

var_dump($result->fetchAll());
?>

以上例程的输出类似于：

array(1) {
  [0]=>
  array(1) {
    ["name"]=>
    string(6) "Alfred"
  }
}