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mysql 分组统计,值在前,条件在后 -- 分组统计,值在前,条件在后, SELECT DATE_FORMAT(del_time,"%Y") as ndate ,DATE_FORMAT(del_time,"%m") as ndate2 ,DATE_FORMAT(del_time,"%d") as 阅读全文
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mysql 多表多字段报表填充查询 当需要2个数据从不同表时: select * from ( select count(id)as org_sum FROM `jnx_drive` WHERE user_id =1 and drive_type =1)as a1, ( select sum(mon 阅读全文
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NMEA-0183 NMEA 0183是美国国家海洋电子协会(National Marine Electronics Association )为海用电子设备制定的标准格式。目前业已成了GPS导航设备统一的RTCM(Radio Technical Commission for Maritime se 阅读全文