MSSQL太麻烦，分页语言级都不支持，得自己写：
1、MySQL、PostgreSQL、SQLite分页：
SELECT * FROM table1
ORDER BY field1
LIMIT $perpage_num OFFSET ($page_index - 1) * $perpage_num
2、MSSQL
SELECT TOP $perpage_num * FROM (
SELECT ROW_NUMBER() OVER(ORDER BY field1) AS __RN, *
FROM table1
) a
WHERE __RN > ($page_index - 1) * $perpage_num
