src/RocknRoot/StrayFw/Database/Postgres/Query/Select.php
public function distinct($distinct)
    {
        if (is_array($distinct) === true) {
            $this->distinct = implode(', ', $distinct);
        } else {
            $this->distinct = $distinct;
        }

        return $this;
    }
public function distinct($distinct)
    {
        if (is_array($distinct) === true) {
            $this->distinct = implode(', ', $distinct);
        } else {
            $this->distinct = $distinct;
        }

        return $this;
    }
Set distinct on clause.

@param  array|string $distinct distinct on clause
@return Select       this