dataone;

inputyear qtr budget;

cards;

2001 3 500

2001 4 400

2003 1 350

;

run;

datatwo;

inputyear qtr sales;

cards;

2001 4 300

2002 1 600

;

run;

proc sql;

select one.*, sales from work.two left join work.one

on one.year=two.year;

quit;

问：left join是先把符合match条件的row拿出来，加上table one不符合条件的row也拿出来。那为何没有2003 1 350这条呢？