SqlQuery::query
---------------
- Crear un query:
$query = SqlQuery::query($this->db)
	->from(static::$table)
	->columns(empty(static::$columns) ? '*' : static::$columns)
	->where($params);

COLUMN
------
- Afegir columnes a un query:
$query->column('(SELECT nom FROM itens WHERE itens.id = ' . static::$table . '.id) AS nom');

- Afegir columnes amb el resultat d'un altre query:
$query->column('numitems',
	SqlQuery::query($this->db, 'SELECT COUNT(*)')
		->from('items')
		->where('items.id = ' . static::$table . '.id')
	);

$query->column(<<< SQL
COALESCE(
		(SELECT "pagina" FROM elements sub WHERE sub.id = elements.id AND sub.context LIKE "pagina:%" LIMIT 1),
		(SELECT "layout" FROM elements sub WHERE sub.id = elements.id AND sub.context LIKE "layout:%" LIMIT 1),
		(SELECT "container" FROM elements sub WHERE sub.id = elements.id AND sub.context LIKE "container:%" LIMIT 1)
	) AS context_tipus
SQL
	);

WHERE
-----
Formats:
	[ field, valor ]
	[ field, op, params ... ]
	[ field, op, [ params ... ] ]
	[ sql ]

- Exemples:
- [ field, valor ]
	[ 'status', 1 ]

- [ field, op, [ params ] ]
	[ 'edad', ['>', '18'] ]

- [ sql ]
	[ "name NOT NULL" ]

- [ field, op, val1, val2, val3 ]
	[ 'nom', 'LIKE',  $var1, '%' ]
	[ 'nom', 'IN',  val1, val2 ]
	[ 'nom', 'BETWEEN',  val1, val2 ]

- [ field, op, [ val1, val2, val3 ]]
	[ 'nom', 'LIKE',  [ $var1, '%' ]]
	[ 'nom', 'IN',  [ val1, val2 ]]
	[ 'nom', 'BETWEEN',  [ val1, val2 ]]

- [ field, [ op, SqlQuery ] ]
	[ 'nom', 'IN',  SqlQuery::query($this->db)
		->from(static::$table)
		->columns(empty(static::$columns) ? '*' : static::$columns)
		->where($params)
	];

- Exemples:
WHERE status = 0
$query->where('status', 0)

WHERE ciutat="igualada"
$query->where('ciutat="igualada"')

WHERE edad > 18
$query->where('edad', ['>', '18'])

WHERE status = 1 AND edad > 18
$query
	->where('status', 1)
	->where('edad', ['>', '18'])

WHERE (status = 1 AND edad > 18)
$query->where([
	['status', 1 ],
	['edad', ['>', 18]] 
])

WHERE ( SELECT ... ) as sq
$query->where( subquery, [ params ... ])

- Evitar aquesta!!! (Està per compatibilitat amb codi antic)
WHERE status = 1
$query->where(['status' => 1 ])

JOIN
----
$query = \Ntlg\Db\SqlQuery::query($this->db)
	->from($this->getTable())
 	->columns(static::$columns, true)
 	->column('items_texts.nom AS nom')
 	->join('LEFT JOIN', 'items_texts texts', 'texts.' . static::$fk . ' = ' . static::$table . '.' . static::$pk, ['idioma' => App::get('language', '')])
 	->where($params);


Exemples de creació de queries
------------------------------
$query = SqlQuery::query($this->db)
	->from($this->getTable())
	->columns(static::$columns, true)
	->column('CONCAT(firstname, " ", lastname) AS fullname')
	->column('user_group.group_id AS group_id')
	->join('LEFT JOIN', 'user_client', 'user_client.client_id = ' . static::$table . '.client_id')
	->where($params);

$query = SqlQuery::query($this->db)
	->from(static::$table)
	->columns(static::$columns, true)
	->column('CONCAT(firstname, " ", lastname) AS fullname')
	->column('ps_alfilbe_client.id_botiga AS id_botiga')
	->column('ps_accuser.id_owner AS id_owner')
	->column('ps_accuser.id_supervisor AS id_supervisor')
	->join('LEFT JOIN', 'ps_alfilbe_client', 'ps_alfilbe_client.id_customer = ' . static::$table . '.id_customer')
	->join('LEFT JOIN', 'ps_accuser', 'ps_accuser.id_customer = ' . static::$table . '.id_customer')
	->where(\Ntlg\Db\SqlQuery::prefixParams($params, static::$table));

- Exemple per afegir condicions:
	$query->where('MATCH(nom, keywords, cpostal, poblacio) AGAINST (:fts IN BOOLEAN MODE)');
	$query->params(['fts' => $this->fts]);

- Exemple de prefixar els params amb el nom de la taula per evitar ambigüitats:
	$query->where($\Ntlg\Db\SqlQuery::prefixParams($params, static::$table));

- Exemple d'adaptació de noms de fields a noms de columnes:
	$params = \Ntlg\Db\SqlQuery::renameColumns($params, [
			'group_id' => 'user_group.group_id',
		]);

Exemples diversos
-----------------
protected function getSelectQuery($params = null)
{
	$query = parent::getSelectQuery($params);

	if (isset($this->etiqueta_id))
	{
		$query->where(array(
			static::$pk => array(
				'IN',
					$this->dbh->sqlQuery('SELECT related_id')
					->from('etiqueta_related')
					->where(array('relation' => static::$fk, 'etiqueta_id' => $this->etiqueta_id))
			)
		));
	}

	if (isset($this->marcador_id))
	{
		$query->where(array(
			static::$pk => array(
				'IN',
					$this->dbh->sqlQuery('SELECT related_id')
					->from('marcador_related')
					->where(array('relation' => static::$fk, 'marcador_id' => $this->marcador_id))
			)
		));
	}

	return $query;
}

protected function getSelectQuery($params = null)
{
	$query = parent::getSelectQuery($params);

	$related = 'forms';
	$related_table = static::$relations[$related]['table'];
	$related_fk = isset(static::$relations[$related]['fk']) ? static::$relations[$related]['fk'] : static::$fk;
	$related_ak = isset(static::$relations[$related]['ak']) ? static::$relations[$related]['ak'] : static::$pk;

	// Afegim una columna addicional...
	$query->column('formscount', $this->dbh->sqlQuery(
			'SELECT COUNT(*)')->from($related_table)->where($related_table . '.' . static::$fk . '=' . static::$table . '.' . static::$pk));

	if (is_array($params))
		$query->where($params);

	return $query;
}

protected function getSelectQuery($params = null)
{
	$query = parent::getSelectQuery($params);

	$query->join('LEFT JOIN', 'forms_related', 'forms_related.form_id=' . static::$table . '.' . static::$pk);

	$column = <<< SQL
COALESCE(
	(SELECT fedns.nombre FROM fedns WHERE fedns.id = forms_related.fed_id LIMIT 1),
		forms_related.fed_id
	) AS federation
SQL;
	$query->column($column);

	$column = <<< SQL
COALESCE(
	(SELECT formtypes.nom FROM formtypes WHERE formtypes.id = forms_related.formtype_id LIMIT 1),
		forms_related.formtype_id
	) AS formtype
SQL;
	$query->column($column);

	if (isset($this->fed_id))
		$params['forms_related.fed_id'] = $this->fed_id;

	if (isset($this->formtype_id))
		$params['forms_related.formtype_id'] = $this->formtype_id;

	if (is_array($params))
		$query->where($params);

	return $query;
}


protected function getSelectQuery($params = null)
{
	$query = parent::getSelectQuery($params);

	if (isset($this->federation_id))
	{
		$sql = <<<SQL
SELECT
	form_id
FROM
	forms_federations f
	INNER JOIN
		forms_types t
		ON f.form_id = t.form_id
SQL;
		$query->where(array(
			static::$pk => array(
				'IN',
					$this->dbh->sqlQuery($sql)
						->where(array('f.federation_id' => $this->federation_id))
			)
		));
	}

	$sql = <<<SQL
SELECT
*
FROM
forms_logins
	item
LEFT JOIN
	forms form ON (form.id = item.form_id)
SQL;
	if (isset($this->federation_id))
		$params['item.federation_id'] = $this->federation_id;

	if (isset($this->type_id))
		$params['item.type_id'] = $this->type_id;

	return $this->dbh->sqlQuery($sql)->where($params);
}


protected function getSelectQuery($params = null)
{
	$query = parent::getSelectQuery($params);

	if (isset($this->agencia_id))
	{
		$sql = <<<SQL
SELECT propietari_id
FROM
	immobles_agencies a
INNER JOIN
	immobles_propietaris p
		ON a.immoble_id = p.immoble_id
SQL;

		$query->where(array(
			static::$pk => array(
				'IN',
					$this->dbh->sqlQuery($sql)
					->where(array('a.agencia_id' => $this->agencia_id))
			)
		));
	}

	if (is_array($params))
		$query->where($params);

	return $query;
}