ODPS内建函数TO_CHAR、TO_DATE的简单使用

1.TO_CHAR:将日期类型date按照format指定的格式转成字符串。
SELECT TO_CHAR('2018-10-27 22:17:55','yyyymmddhhmiss') as stg_rksj FROM dwd_dz_gj_ryjghxx_di;
返回20181027221755
2.TO_DATE:将一个format格式的字符串date转成日期值，返回Datetime类型，格式为yyyy-mm-dd hh:mi:ss 。若任意一个输入的参数为NULL，则返回NULL值。
SELECT TO_DATE('20181027221755','yyyymmddhhmiss') as dw_rksj FROM dwd_dz_gj_ryjghxx_di;
返回2018-10-27 22:17:55

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