//按月统计近六个月的数据

SELECT

TO_CHAR ( drive_lic_iss_ctf_dt,'yyyy-MM' ),COUNT (*) FROM T02_PRACT_H WHERE to_char(drive_lic_iss_ctf_dt,'yyyy-mm') > to_char(sysdate-interval'6'month,'yyyy-mm') AND to_char(sysdate+interval'1'month,'yyyy-mm') > to_char(drive_lic_iss_ctf_dt,'yyyy-mm') GROUP BY TO_CHAR ( drive_lic_iss_ctf_dt,'yyyy-MM' ) order BY TO_CHAR ( drive_lic_iss_ctf_dt,'yyyy-MM' ) desc ;