Views join handler plugins

Handler plugins for Views table joins.

Handler plugins help build the view query object. Join handler plugins handle table joins.

Views join handlers extend \Drupal\views\Plugin\views\join\JoinPluginBase. They must be attributed with \Drupal\views\Attribute\ViewsJoin attribute, and they must be in namespace directory Plugin\views\join.

Here are some examples of configuration for the join plugins.

For this SQL:

LEFT JOIN {two} ON one.field_a = two.field_b

Use this configuration:

$configuration = array(
  'table' => 'two',
  'field' => 'field_b',
  'left_table' => 'one',
  'left_field' => 'field_a',
  'operator' => '=',
);
$join = Views::pluginManager('join')
  ->createInstance('standard', $configuration);

Note that the default join type is a LEFT join when 'type' is not supplied in the join plugin configuration.

If an SQL expression is needed for the first part of the left table join condition, 'left_formula' can be used instead of 'left_field'. For this SQL:

LEFT JOIN {two} ON MAX(one.field_a) = two.field_b AND one.field_c = 'some_val'

Use this configuration:

$configuration = array(
  'table' => 'two',
  'field' => 'field_b',
  'left_table' => 'one',
  'left_formula' => 'MAX(one.field_a)',
  'operator' => '=',
  'extra' => array(
    0 => array(
      'left_field' => 'field_c',
      'value' => 'some_val',
    ),
  ),
);
$join = Views::pluginManager('join')
  ->createInstance('standard', $configuration);

For this SQL:

INNER JOIN {two} ON one.field_a = two.field_b AND one.field_c = 'some_val'

Use this configuration:

$configuration = array(
  'type' => 'INNER',
  'table' => 'two',
  'field' => 'field_b',
  'left_table' => 'one',
  'left_field' => 'field_a',
  'operator' => '=',
  'extra' => array(
    0 => array(
      'left_field' => 'field_c',
      'value' => 'some_val',
    ),
  ),
);
$join = Views::pluginManager('join')
  ->createInstance('standard', $configuration);

For this SQL:

INNER JOIN {two} ON one.field_a = two.field_b AND two.field_d = 'other_val'

Use this configuration:

$configuration = array(
  'type' => 'INNER',
  'table' => 'two',
  'field' => 'field_b',
  'left_table' => 'one',
  'left_field' => 'field_a',
  'operator' => '=',
  'extra' => array(
    0 => array(
      'field' => 'field_d',
      'value' => 'other_val',
    ),
  ),
);
$join = Views::pluginManager('join')
  ->createInstance('standard', $configuration);

For this SQL:

INNER JOIN {two} ON one.field_a = two.field_b AND one.field_c = two.field_d

Use this configuration:

$configuration = array(
  'type' => 'INNER',
  'table' => 'two',
  'field' => 'field_b',
  'left_table' => 'one',
  'left_field' => 'field_a',
  'operator' => '=',
  'extra' => array(
    0 => array(
      'left_field' => 'field_c',
      'field' => 'field_d',
    ),
  ),
);
$join = Views::pluginManager('join')
  ->createInstance('standard', $configuration);

Here is an example of a more complex join:

class JoinComplex extends JoinPluginBase {
  public function buildJoin($select_query, $table, $view_query) {

    // Add an additional hardcoded condition to the query.
    $this->extra = 'foo.bar = baz.boing';
    parent::buildJoin($select_query, $table, $view_query);
  }

}

See also

Plugin API

Parent topics

File

core/modules/views/src/Plugin/views/join/JoinPluginBase.php, line 8

Classes

Name	Location	Description
JoinPluginBase	core/modules/views/src/Plugin/views/join/JoinPluginBase.php	Represents a join and creates the SQL necessary to implement the join.
ViewsJoin	core/modules/views/src/Annotation/ViewsJoin.php	Defines a Plugin annotation object for views join plugins.