如何优雅统计知识库文件个数与子集下不同文件夹文件个数

        SELECT
            space_code as code,
            COUNT(*) AS code_count
        FROM
            kb_page
        WHERE
            type != 'FOLDER'
            AND status = 'PUBLISHED'
            AND tenant_id = #{tenantId}
            AND space_code IN
            <foreach collection="spaceCodesList" item="spaceCode" open="(" separator="," close=")">
                #{spaceCode}
            </foreach>
        GROUP BY
            space_code;

            for (PageTreeResp item : result) {
                if (PageTypes.FOLDER.name().equals(item.getType())) {
                    int fileCount = countFilesByFullParentCode(item.getCode(), item.getSpaceCode(), sysUserInfo.getTenantId());
                    item.setCodeCount(String.valueOf(fileCount));
                }
            }
​
## 具体的代码计算逻辑
   /**
     * 使用数据库 full_parent_code 统计文件夹下所有子孙文件数量（排除文件夹本身，type != FOLDER）
     * 保证同一租户、同一空间内统计。
     */
    private int countFilesByFullParentCode(String folderCode, String spaceCode, String tenantId) {
        LambdaQueryWrapper<KbPage> wrapper = new LambdaQueryWrapper<>();
        wrapper.eq(KbPage::getTenantId, tenantId);
        wrapper.eq(KbPage::getSpaceCode, spaceCode);
        wrapper.eq(KbPage::getStatus, KBPageStatus.PUBLISHED.name());
        // full_parent_code 中以逗号分隔父级编码，使用分隔符匹配避免误匹配
        wrapper.apply("INSTR(CONCAT(',', full_parent_code, ','), CONCAT(',', {0}, ',')) > 0", folderCode);
        // 只统计非文件夹类型
        wrapper.ne(KbPage::getType, KbPageTypes.FOLDER.name());
        return Math.toIntExact(kbPageMapper.selectCount(wrapper));
    }

-- 伪 SQL
WHERE ...
  AND INSTR(CONCAT(',', full_parent_code, ','), ',abc,') > 0