select ryrq,extract (year from ryrq),extract (month from ryrq),extract (day from ryrq) from zy_brry where zyh=6830

上面的方法获取的都是把0省略后的值，目标是获取2016、04、02 

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select csny,substr(to_char(csny,‘yyyy‘),1,4) csyear,‘mm‘),2) csmonth，
substr(to_char(csny,‘dd‘),2) csday from zy_brry where zyh=6830

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上面这种方法截取一下也可以，

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这个substr截取日期好像规则与截取字符窜有点区别

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select substr(to_char(ryrq,4) ryyear,substr(to_char(ryrq,2) rymonth，substr(to_char(ryrq,2) ryday，substr(to_char(ryrq,‘hh‘),2) ryhour,substr(to_char(cyrq,4) cyyear,2) cymonth，substr(to_char(cyrq,2) cyday，substr(to_char(cyrq,2) cyhour,2) csmonth，substr(to_char(csny,2) csday from zy_brry where zyh=43439