摘要： 例子：select distinct substr(name,5) from hvm_cfg_data where stationid='12010013'查询表中name字段从第5个字符以后的字符串。 select distinct substr(name,5,2) from hvm_cfg_data where stationid='12010013'查询表中name字段从第5个字符开始2个字... 阅读全文