core/SqlSelector.php
public function unionAll(SqlSelector $selector)
    {
        if ($selector == null) {
            return $this;
        }
        if ($this->unionItem == null) {
            $this->unionItem = [];
        }
        $this->unionItem[] = new SqlUnionItem($selector, true);
        return $this;
    }
public function unionAll(SqlSelector $selector)
    {
        if ($selector == null) {
            return $this;
        }
        if ($this->unionItem == null) {
            $this->unionItem = [];
        }
        $this->unionItem[] = new SqlUnionItem($selector, true);
        return $this;
    }
联合,运行结果重复
@param SqlSelector $selector
@return $this