Hi, Just an thought: wouldn't you have inverted the 'drug' and the constants ('EC0225', 'EC0489', 'EC145') ? In this case, the 'unique' keywork would be useless as you are using a group by in all of your select statements. Regards, Florent /*** first dose dates ***/ proc sql; create table ec225dates as select patno, 'EC0225' as drug, min(admindt) as firstdosedt format date9. from ec225.ec225adm group by patno; create table ec489dates as select patno, 'EC0489' as drug, min(admindt) as firstdosedt format date9. from ec489.ec0489 group by patno; create table ec145dates as select patno, 'EC145' as drug, min(admindt) as firstdosedt format date9. from fv01.ec145adm group by patno; quit; data dosedates; set ec225dates ec489dates ec145dates; run;
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