/**
* @return string
*/
public function prepareExists()
{
$columns = empty($this->_columns) ? '*' : implode(', ', $this->_columns);
$tables = implode(', ', $this->_tables);
$where = empty($this->_where) ? '' : ' WHERE ' . $this->_where->prepare();
$having = empty($this->_having) ? '' : ' HAVING ' . $this->_having->prepare();
$join = empty($this->_join) ? '' : ' ' . $this->_join->prepare();
$limit = ' LIMIT 0, 1';
$group = empty($this->_group) ? '' : ' GROUP BY ' . $this->_group;
return 'SELECT ' . $columns . ' FROM ' . $tables . $join . $where . $group . $having . $limit;
}
/**
* @param SelectQuerySource $source source to which join operation should be applied
* @param SqlJoinMethod $joinMethod method to use when performing join
* @param SqlFieldArray $identicalColumns set of column names that should be used in joining
*/
function __construct(SelectQuerySource $source, SqlJoinMethod $joinMethod, SqlFieldArray $identicalColumns)
{
$this->identicalColumns = $identicalColumns;
parent::__construct($source, $joinMethod);
}
/**
* @param SelectQuerySource $source source to which join operation should be applied
* @param SqlJoinMethod $joinMethod method to use when performing join
* @param IExpression $condition condition to use when performing join
*/
function __construct(SelectQuerySource $source, SqlJoinMethod $joinMethod, IExpression $condition)
{
$this->condition = $condition;
parent::__construct($source, $joinMethod);
}