在php7.3及以上版本中，会出错

[lzj500]

代码位置 ：\topthink\think-orm\src\db\BaseQuery.php 原代码：

public function field($field)
    {
        if (empty($field)) {
            return $this;
        } elseif ($field instanceof Raw) {
            $this->options['field'][] = $field;
            return $this;
        }

        if (is_string($field)) {
            if (preg_match('/[\<\'\"\(]/', $field)) {
                return $this->fieldRaw($field);
            }

            $field = array_map('trim', explode(',', $field));
        }

        if (true === $field) {
            // 获取全部字段
            $fields = $this->getTableFields();
            $field  = $fields ?: ['*'];
        }

        if (isset($this->options['field'])) {
            $field = array_merge((array) $this->options['field'], $field);
        }
        $this->options['field'] = array_unique($field);

        return $this;
    }

修改为

public function field($field)
  {
      if (empty($field)) {
          return $this;
      } elseif ($field instanceof Raw) {
          $this->options['field'][] = $field;
          return $this;
      }

      if (is_string($field)) {
          if (preg_match('/[\<\'\"\(]/', $field)) {
              return $this->fieldRaw($field);
          }

          $field = array_map('trim', explode(',', $field));
      }

      if (true === $field) {
          // 获取全部字段
          $fields = $this->getTableFields();
          $field  = $fields ?: ['*'];
      }

      if (isset($this->options['field'])) {
          $field = array_merge((array) $this->options['field'], $field);
      }
      $this->options['field'] = @array_unique($field);

      return $this;
  }

$this->options['field'] = array_unique($field); 这一行增加一个@，忽略报错，否则有时联表分组查询后，先查count，再查select会报错。如下图：