src/db/BuildSql.php
public function value($field = '')
    {

        if ($field) {
            $this->field($field);
        }

        $this->limit(1);
        $this->bulidSql('SELECT');

        $result = $this->query();

        if ($result) {
            $data = $result->fetchColumn();
        }

        return !empty($data) ? $data : '';

    }
public function value($field = '')
    {

        if ($field) {
            $this->field($field);
        }

        $this->limit(1);
        $this->bulidSql('SELECT');

        $result = $this->query();

        if ($result) {
            $data = $result->fetchColumn();
        }

        return !empty($data) ? $data : '';

    }
获取单个字段内容
@date   2018-04-06T21:35:17+0800
@author ChenMingjiang
@param  [type]                   $field [description]
@return [type]                          [description]