Editor's Note: hongxianzhang's code below shows how to use the INPUT function along with the YYMMDDw.d informat, which was suggested by LinusH. The INPUT function along with the YYMMDDw.d informat allow you to convert a numeric string in the form yymmdd into a SAS date.
DATA SET2;
SET SET1;
DATE2 = INPUT(PUT(DATE1,8.),YYMMDD8.);
FORMAT DATE2 YYMMDD8.;
RUN;
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