需求：找出为””或者为null的行数

错误版本

const count = await Model.count({
      where: {
        $or: [
          { value: null },
          { value: '' },
        ],
      },
    });

sql: SELECT count(*) AS `count` FROM `setting` AS `setting` WHERE ((`setting`.`deleted_at` > '2019-04-16 10:02:39' OR `setting`.`deleted_at` IS NULL) AND (`setting`.`required` = true AND (`setting`.`value` IS NULL OR `setting`.`value` = '\"\"')));

• 原因：nodejs sequelize库防注入测试，Model.count把”转义了’\”\”‘

正确版本

const count = await this.app.model.Setting.count({
      where: {
        $or: [
          { value: null },
          literal('value = ""'),
        ],
      },
    });