https://communities.sas.com/t5/SAS-Programming/don-t-understand-this-one-line-in-my-code/m-p/761324#M240896 <P>I think you've got your start and end dates mixed up. This might work better:</P> <PRE><CODE class=" language-sas">proc sql; create table cares_count as select distinct a.pat_id, 1 as flag from fake_data a, fake_data b where a.pat_id = b.pat_id and 0 &lt; intck('day', a.visit_date, b.visit_date) &lt; 366; quit;</CODE></PRE> Fri, 13 Aug 2021 01:02:39 GMT SASKiwi 2021-08-13T01:02:39Z https://communities.sas.com/t5/SAS-Programming/don-t-understand-this-one-line-in-my-code/m-p/761319#M240891 <P>I have the below code.</P> <P>&nbsp;</P> <PRE><CODE class=" language-sas">proc sql; create table cares_count as select distinct a.pat_id, 1 as flag from fake_data a, fake_data b where a.pat_id = b.pat_id and b.visit_date &gt; a.visit_date and intck('day', b.visit_date, a.visit_date) &lt; 366; quit;</CODE></PRE> <P>Can you tell me what</P> <PRE><CODE class=" language-sas">b.visit_date &gt; a.visit_date</CODE></PRE> <P>is doing? I don't understand this line.</P> <P>Here is some fake data.</P> <PRE><CODE class=" language-sas">data fake_data; input pat_id $ visit_date:MMDDYY10.; format visit_date MMDDYY10.; datalines; 12393 8/28/1982 12393 6/16/1993 12393 12/21/1982 12534 11/26/2010 12601 6/3/2021 12601 10/11/2015 12601 12/17/1983 12601 9/1/2019 12601 4/27/2000 12601 5/5/1986 12703 1/30/1987 12703 4/24/1988 12724 11/16/2021 12724 11/24/1985 12724 12/22/2016 12724 9/11/2014 12732 11/10/2016 12732 12/6/1986 12732 9/11/2001 12901 8/11/2019 13000 9/27/2007 13000 3/26/1987 13000 3/16/2011 13146 11/12/1991 13226 5/28/1983 13254 11/25/2022 13331 4/6/1996 13331 5/24/2020 13331 6/14/1985 13387 12/29/2009 13643 5/29/1985 13643 2/24/1985 13643 12/21/2018 14288 10/27/1987 14311 2/18/1984 14311 2/8/1996 14311 1/10/2023 14311 6/23/2013 14311 1/8/1996 14393 9/23/2017 14472 3/7/1997 14472 2/1/2005 14472 3/7/2001 15296 1/5/2016 15296 7/26/1992 15296 5/23/1983 15296 2/23/1983 15438 11/14/2013 15438 4/30/2003 15438 8/18/1995 15452 12/28/2022 15452 12/27/1996 15452 8/28/1992 15480 11/23/1988 15483 3/19/1999 15483 1/8/1999 15483 10/18/2001 15790 7/31/1984 15790 3/2/1984 15790 6/16/1983 15790 1/6/1993 15790 3/28/2011 15970 2/22/2003 16058 6/2/1985 16058 11/11/2009 16058 3/1/2013 16058 12/17/1982 16058 1/7/2005 16058 11/13/1999 16058 8/30/1990 16058 8/21/2019 16094 5/28/1983 16258 1/12/1985 16268 6/22/2007 16268 2/5/2017 16396 2/28/1994 16406 9/17/2013 16406 1/1/2007 16586 5/19/1989 16676 5/9/2015 16676 8/25/2018 16774 4/21/1992 16774 9/17/1983 17001 6/19/1997 17206 9/26/2001 17257 3/28/2013 17290 3/7/1987 17290 12/27/1995 17343 6/17/2021 17343 10/16/1988 17348 7/21/2011 17451 12/3/1991 17451 11/2/1989 17451 7/31/1989 17730 3/18/2022 18118 9/30/2002 18118 10/9/1986 18275 5/31/2004 18275 7/10/2016 18391 1/16/2017 18391 4/7/2017 18391 10/12/2003 18391 2/11/2015 18391 11/13/1994 18391 5/29/2009 18406 7/24/2004 18406 5/15/2017 18406 2/17/1987 18818 10/8/2001 19260 7/18/2008 19379 7/25/2019 19379 4/6/1988 19379 7/27/2006 19602 5/8/2004 19602 7/5/1984 19602 6/12/2003 19602 12/3/2021 19851 10/20/2017 19851 5/26/2009 19851 10/30/2021 19851 8/7/2018 20193 10/11/2008 20196 4/28/2007 20230 1/17/2021 20351 1/18/1999 20472 2/23/1993 20512 6/29/1985 20512 7/17/2000 20656 5/24/2008 20656 1/2/2002 20719 8/3/2012 20719 2/8/2005 20791 4/8/2018 20791 1/10/2014 20947 5/5/2020 20947 12/12/2013 20947 4/28/2002 20947 7/13/2002 21014 5/6/1986 21014 4/29/2017 21014 12/9/2020 21014 11/10/1984 21142 2/10/1999 21142 4/21/1991 21142 5/29/1997 21558 1/1/1991 21660 8/7/2021 21808 3/9/1998 22123 11/22/1989 22123 4/25/2013 22208 6/15/2011 22208 2/28/2007 22208 8/19/2002 22220 9/8/2002 22333 5/19/2000 22333 6/19/2003 22333 1/14/2007 22348 2/27/2010 22474 6/1/2017 22493 2/19/2019 22493 6/13/2003 22738 4/12/1994 22738 11/5/1994 22799 8/24/1995 22799 10/31/1989 22799 11/6/2022 22799 2/23/1993 22886 10/27/2018 22886 12/12/2002 22886 2/18/1989 22886 12/6/2012 22886 8/12/2018 22886 1/27/1988 22888 1/27/2021 22888 11/11/2009 22888 2/3/1989 22888 1/12/2005 23130 4/14/2013 23308 2/13/1994 23308 12/8/2017 23646 6/28/1987 23646 1/3/2002 23649 3/31/2012 23694 5/17/1982 23736 11/2/1989 24074 10/7/2022 24074 1/17/2023 24074 8/28/2005 24222 10/27/2013 24222 2/3/2021 24247 9/1/2017 24486 11/28/1988 24486 1/31/2008 24746 1/9/2008 24774 5/14/2021 24827 6/8/2015 24860 9/2/2004 24860 10/28/2000 25132 4/21/1990 25219 11/17/2001 25639 7/19/2014 25639 6/18/2006 25639 10/16/1984 25639 6/26/2015 25707 9/25/2015 25707 8/13/1995 25717 10/28/1997 25742 5/26/1995 25773 5/10/2016 25773 7/4/1986 25869 10/30/1997 25882 4/21/2018 25882 9/6/1984 25958 5/20/1993 25958 3/23/2007 25958 11/23/2021 25993 5/11/2003 26001 6/11/2002 26001 11/3/1983 26001 3/19/1991 26001 8/15/2010 26051 1/13/2017 26051 12/9/2017 26217 7/8/2014 26217 6/13/2001 26460 7/27/2011 26473 2/16/2013 26540 4/20/2000 26540 10/27/1993 26540 11/21/1989 26658 5/21/1986 26838 3/8/2004 26838 3/10/1997 26838 12/13/1988 26868 8/7/2005 26868 4/19/2006 26868 8/26/2020 27115 8/2/1983 27143 6/26/1992 27154 5/21/2006 27243 6/10/2016 27243 10/17/2011 27243 10/30/2001 27243 12/16/1999 27243 2/29/2000 27338 3/23/2000 27462 1/18/2010 27462 6/19/2002 27481 4/10/2003 27481 2/20/2000 27504 1/27/2021 27504 11/29/1987 27528 1/25/2010 27528 9/29/2022 27528 11/6/2000 27528 4/17/1984 27559 5/5/1988 27605 6/25/1997 27755 8/31/1990 27886 4/4/1985 27886 4/14/1991 27886 6/13/1989 27886 9/29/2010 27886 3/29/2017 27886 11/17/2004 28041 1/4/2004 28041 3/12/1988 28041 9/2/1985 28041 3/31/2013 28041 7/11/1985 28041 2/11/2017 28192 5/24/1982 28192 1/24/2009 28192 11/25/2011 28230 7/5/1999 28230 9/8/2015 28230 1/7/1984 28230 7/18/2014 28245 5/23/2012 28809 1/5/2009 28809 4/1/2020 28809 2/21/2015 28809 5/19/1987 28809 3/28/1996 28985 1/4/1986 28985 3/31/2013 28985 2/1/1987 28985 6/5/2013 28985 5/19/1986 29028 8/3/2018 29028 2/19/2014 29028 7/14/2019 29033 4/26/2000 29033 8/12/2021 29099 7/26/2007 29233 10/24/2009 29233 6/17/2000 29233 3/30/1986 29566 3/5/2007 29648 4/24/2002 30266 8/15/2002 30266 5/10/2021 30532 12/7/2000 30532 7/10/1982 30532 4/2/1985 30572 8/21/2004 30572 5/18/1999 30572 4/8/2019 30606 7/18/1994 30613 4/12/1990 30767 6/8/2003 30783 1/26/1994 30783 4/8/1998 30871 7/29/1988 30948 11/23/1993 31039 6/26/2014 31060 8/1/2000 31060 6/10/2014 31060 10/6/1988 31151 12/11/1991 31151 8/21/1991 31151 2/25/2023 31151 10/8/2011 31192 11/25/1988 31192 8/14/2003 31486 12/1/1994 31614 12/3/2019 31652 10/25/1999 31707 11/16/2012 31799 1/3/1995 31860 1/29/2009 32039 3/5/2009 32442 7/28/2011 32506 6/25/2005 32506 5/18/1986 32506 11/17/2017 32506 3/18/2011 32596 4/28/2015 32699 1/8/2017 32980 11/23/2009 32980 10/27/2021 32980 4/19/2002 33742 3/30/2005 33742 8/2/1982 33745 4/17/1993 33911 1/22/2023 33921 5/11/2022 34240 11/28/2013 34536 6/27/2007 34536 8/28/2000 34582 9/15/2003 34582 12/21/1994 34582 3/18/2016 34582 2/20/2023 34582 6/23/1998 34615 10/10/1995 34615 10/1/2010 34981 4/10/1992 34981 1/22/2010 35001 12/30/2001 35001 8/12/2020 35041 10/1/1984 35041 5/19/2022 35113 2/5/2002 35113 7/3/2004 35189 8/28/2009 35189 12/17/2003 35240 4/3/2013 35240 9/18/1996 35246 11/3/1984 35300 4/19/1988 35300 3/8/2016 35300 8/13/2012 35374 5/4/2000 35374 8/25/2018 35374 12/31/2004 35532 3/14/1994 35951 11/15/2005 35963 8/12/2006 35972 3/23/1998 35972 9/23/2017 36049 5/7/2013 36049 1/3/2013 36049 10/3/1994 36049 3/27/2003 36075 8/13/1993 36090 5/22/1995 36090 4/14/1995 36125 9/18/1989 36434 10/23/2017 36434 3/4/2001 36460 9/6/2004 36460 5/20/1993 36494 1/4/1990 36494 10/17/2008 36519 7/7/1996 36519 5/18/2019 36519 3/12/1996 36519 10/21/2008 36519 10/4/1989 36519 7/24/1987 36730 2/7/2011 36730 7/21/2021 36730 11/28/2004 36862 8/18/2003 36862 12/20/2017 36932 4/14/1994 37034 2/12/2013 37463 6/13/2009 37642 7/30/2018 37642 8/1/2001 37778 9/13/2002 37831 1/30/2009 37974 3/20/1989 37974 4/27/2018 37974 9/15/1998 38011 4/5/1992 38011 11/27/1988 38198 8/28/1994 38321 6/17/2017 38321 7/31/2003 38347 8/3/1985 38375 1/29/2023 38490 8/23/2003 38563 12/15/2008 38609 11/28/2022 38799 2/10/1992 38799 2/1/2019 38906 6/19/2006 38911 9/9/2018 38911 10/13/1982 38911 1/4/1985 39032 4/7/2022 39032 5/27/2008 39054 1/8/1992 39054 3/8/1992 39069 10/5/2021 39069 1/7/2002 39155 2/17/2013 39308 8/2/1989 39406 4/19/2011 39406 4/12/2009 39474 9/3/1996 40339 5/5/1986 40339 12/20/2009 40449 5/9/1984 40449 12/2/2016 40498 10/9/2011 40659 10/18/1987 41030 11/1/2011 41202 3/28/2002 41202 9/24/2016 41202 5/10/2014 41220 1/4/2005 41378 8/16/1989 41378 4/1/1986 41378 3/8/1995 41479 6/30/1996 41479 11/3/1985 41479 6/10/1998 41479 4/17/2014 41616 9/13/1993 41616 3/21/2004 41854 3/30/2008 41869 12/16/2013 41869 5/30/2010 41869 8/4/1993 41936 3/2/2017 42063 10/8/2008 42063 11/30/2000 42063 1/8/2008 42063 2/26/2017 42063 12/17/1989 42063 9/9/1995 42079 6/24/2011 42337 6/10/1986 42337 5/14/1987 42337 6/16/2010 42337 4/8/2002 42337 8/15/2006 42337 8/24/2009 42337 3/27/2006 42337 5/5/2015 42495 7/16/2008 42495 2/9/2009 42495 7/16/1983 42595 9/16/1989 42797 6/20/1997 42797 7/28/2000 42797 12/19/1982 42841 8/3/1991 42841 7/3/1997 42841 4/16/1984 43156 9/21/1990 43258 10/1/2004 43618 2/16/1988 43994 8/5/2003 44227 5/15/2014 44271 12/25/2021 44328 12/26/1995 44328 11/15/2010 44328 2/9/2002 44328 6/23/2003 44358 2/1/1993 44724 4/12/1986 45094 3/30/2005 45094 8/23/2010 45145 10/2/2015 45145 8/23/2018 45176 12/20/2013 45176 11/16/2000 45176 9/10/1984 45313 3/12/2021 45313 5/29/2011 45505 11/29/2006 45651 5/2/1986 45742 2/8/2014 45742 8/9/1991 45871 2/4/1994 45871 6/13/2007 45871 7/13/1982 45871 1/27/2019 45890 2/17/2001 45905 11/21/2000 46665 1/1/2021 46665 8/10/2000 46665 6/2/1986 46682 10/10/2009 46794 4/26/2010 46863 4/8/1992 46874 8/20/1999 46874 2/15/2012 46874 8/1/2016 47304 6/2/2003 47597 3/3/1983 47597 10/28/2001 47967 2/11/2015 47998 3/13/2016 48041 5/8/1996 48041 5/14/2008 48042 1/10/2019 48042 9/6/2005 48042 4/5/2004 48168 10/8/2008 48197 7/3/2021 48197 5/9/2016 48197 10/10/1983 48255 8/9/2018 48272 3/6/1985 48377 5/24/2001 48555 3/16/1999 48555 2/19/2011 48555 10/31/2018 48661 3/27/1990 48782 6/18/1994 48860 4/13/2018 48870 9/4/1989 48870 7/29/2012 48870 7/31/1998 48892 3/21/1987 48892 9/25/2002 48892 12/1/1985 48919 4/18/1982 48919 3/2/1992 48919 2/10/1993 49159 7/3/2019 49159 8/15/1982 49219 11/25/2018 49219 12/4/2000 49219 10/1/1986 49219 5/15/2000 49277 9/19/2016 49277 8/14/2003 49599 8/9/1990 49599 10/27/1998 49638 8/19/1991 49638 9/22/1982 49723 6/25/1991 49723 12/11/2019 49723 11/1/1993 49747 1/3/1990 49747 9/21/2017 49808 12/20/2022 49808 8/4/2012 49808 2/1/1986 49839 8/14/2006 49839 11/25/2009 49839 4/27/2021 49971 1/11/2015 49988 9/23/2011 50085 5/24/2009 50085 10/11/2001 50100 10/6/2005 50103 1/24/2013 50184 7/19/2005 50219 6/21/1991 50291 11/28/1988 50598 11/15/1996 50642 10/11/2013 50642 9/3/1998 50642 10/16/1985 50642 11/15/2013 50755 12/8/1994 50755 3/21/2007 50993 9/5/1999 50993 5/27/2014 51059 6/24/1986 51092 3/29/2010 51334 10/6/2005 51334 3/23/1992 51349 12/20/1997 51494 9/26/2011 51683 6/2/1994 51683 11/23/2002 51683 8/18/2006 51784 5/25/2018 51829 3/17/2015 52036 12/8/2005 52036 11/18/1994 52076 1/3/2011 52076 4/10/1987 52124 4/12/2020 52124 12/7/2000 52298 7/6/1998 52359 3/31/1989 52425 6/6/1999 52425 8/25/2003 52458 9/12/1995 53572 10/23/2021 53624 12/20/1989 53638 4/29/1991 53752 5/1/1999 53883 10/29/1996 53909 10/10/2004 53909 7/9/1985 54149 3/21/1983 54432 11/11/1987 54484 12/14/1992 54484 12/30/2003 54484 9/2/1998 54591 11/27/2019 54591 8/10/1992 54642 4/9/1998 54713 5/23/1985 54734 8/6/2003 54734 12/28/1993 54734 3/21/2010 54750 9/4/2014 54808 3/12/2001 54808 2/17/2007 54808 10/31/2011 54856 10/18/2022 54856 12/7/2020 54856 12/7/1982 54856 2/25/1990 54856 1/7/2014 54856 8/5/1987 54856 9/23/1995 54856 5/19/1999 54941 3/6/1991 54941 1/30/1989 54941 1/30/2001 54941 9/24/2010 54941 6/13/1989 54941 5/11/2020 54964 3/9/2017 54964 3/18/2019 54964 12/20/2020 55105 3/10/2005 55105 8/31/2018 55446 7/13/1996 55511 2/11/2004 55705 8/6/1998 55858 2/18/1992 55997 12/23/1983 56030 1/18/2003 56030 5/14/2009 56030 8/20/1984 56341 11/7/2004 56341 12/5/2016 56341 7/13/2014 56341 5/9/2000 56341 3/14/1988 56341 2/3/2012 56385 5/9/1988 56423 5/7/1998 56423 10/22/2001 56423 12/20/2011 56529 8/26/1994 56529 7/19/2001 56613 11/4/2008 56693 1/5/2013 56715 10/22/1994 56898 3/3/2023 56898 9/20/1991 56898 7/12/2019 56923 3/4/1996 56934 8/30/1987 56934 4/6/2003 56966 1/12/2011 57020 10/28/2020 57020 11/24/1982 57020 6/29/2003 57020 3/7/1989 57083 2/25/2012 57083 10/15/2020 57083 4/3/1985 57083 1/28/1992 57083 7/25/1998 57202 8/23/1996 57202 6/10/1982 57202 6/16/1997 57202 10/13/1984 57202 10/16/1997 57202 1/21/2015 57202 6/29/1985 57243 4/6/2012 57243 6/12/2006 57243 5/9/1986 57326 5/4/2001 57326 11/17/1991 57364 1/13/2007 57403 1/12/2006 57438 11/5/2009 57585 3/10/2021 57859 3/18/2001 58029 4/26/1986 58029 8/20/2020 58154 1/12/1999 58154 8/16/1998 58154 2/17/1983 58154 3/28/2002 58154 11/27/2003 58219 12/3/2001 58219 7/21/1996 58570 5/3/2020 58572 2/18/1989 58572 3/26/2003 58572 11/26/1990 58572 11/16/2016 58572 12/22/2016 58572 4/9/2013 58572 2/3/1986 58753 9/16/2002 58753 4/30/2015 58770 1/16/2023 58770 3/17/1982 58770 9/28/2017 58770 7/3/1986 58770 5/17/1984 58770 8/19/2019 58916 10/29/2021 58974 6/7/2004 58974 5/26/2010 59171 6/30/2009 59567 4/8/1987 59742 7/30/2019 59742 9/27/1991 59742 3/29/2012 59742 6/25/2020 59742 5/22/1986 59784 10/18/2003 60198 9/23/2018 60223 12/11/2014 60223 8/1/2007 60223 3/6/1996 60261 9/12/2000 60261 4/18/2018 60261 6/25/1992 60261 3/6/2006 60360 6/2/1997 60360 10/7/1999 60734 5/21/2010 61317 3/22/2022 61397 8/21/1995 61397 12/4/2003 61521 8/5/1987 61521 8/6/2006 61521 9/21/2003 61717 5/24/2012 61717 3/30/1988 61717 9/3/2021 61741 5/3/2010 61866 11/17/2013 61893 4/12/1982 61893 6/28/1991 61893 7/24/1985 62128 8/18/1983 62133 5/21/2012 62133 3/16/2013 62133 12/5/1991 62133 2/3/2013 62133 8/15/1991 62133 3/13/1987 62439 7/25/1993 62732 5/19/1989 62732 3/14/2016 62927 7/24/2014 62927 6/26/2019 63080 7/8/2004 63167 1/19/1992 63190 2/16/1994 63373 10/3/2012 63373 9/19/2002 63373 12/27/1992 63378 4/23/2018 63486 8/22/2022 63486 8/9/2005 63612 10/10/2003 63700 8/2/2017 63832 11/3/2015 63832 6/18/1992 63832 8/6/2000 63832 6/7/2017 64130 4/6/1985 64130 9/1/2019 64225 3/31/2010 64225 8/3/1982 64290 5/5/1992 64290 6/19/1996 64403 1/8/2020 64505 12/31/2017 64505 9/10/2015 64505 6/13/1984 64513 10/20/2016 64513 6/6/1990 64573 6/15/2016 64690 9/15/2003 64690 10/23/2001 64690 1/23/1993 64690 2/6/1999 64690 6/8/2013 64904 9/22/2009 64925 4/2/1985 64925 8/29/2003 65016 4/24/2011 65141 4/22/2010 65307 11/2/2016 65307 7/7/2016 65385 11/9/1987 65522 1/16/2008 65585 11/3/2013 65585 12/12/1997 65586 10/24/1992 65586 12/15/2006 65673 8/12/1993 65673 8/14/2017 65759 11/3/1999 65767 8/31/2013 66122 4/24/1983 66122 9/1/2020 66122 1/9/1998 66136 7/12/2001 66136 6/5/1995 66136 10/22/2021 66268 1/13/1983 66410 6/24/2012 66508 4/14/2009 66508 1/25/1983 66508 5/17/2009 66673 6/26/2022 66856 4/23/2022 66856 4/19/2011 66856 2/3/2021 66856 7/5/2021 66861 10/2/1992 66926 7/13/2003 67084 2/7/2004 67159 9/4/2014 67242 5/22/2004 67242 7/6/1988 67242 2/15/2008 67291 12/31/1986 67291 4/27/1995 67374 11/25/2001 67374 7/4/2000 67374 3/14/1986 67374 6/9/2005 67374 11/22/2011 67400 9/28/2012 67410 5/4/1989 67410 3/3/2008 67410 7/1/2008 67410 8/31/2005 67410 11/17/2021 67410 1/9/1998 67410 6/11/2019 67478 8/27/2011 67478 10/25/1982 67478 12/22/2014 67478 8/12/2014 67512 10/13/2007 67512 1/22/2011 67760 10/12/2017 67760 4/26/1995 68035 5/13/1987 68138 9/12/1985 68169 5/4/1986 68169 7/29/1997 68275 7/19/2022 68275 11/30/2015 68381 11/6/1997 68381 5/17/1998 68403 3/15/1992 68403 12/8/1984 68403 10/24/2017 68441 9/19/2002 68441 1/24/2021 68441 10/28/1992 68525 11/16/2002 68560 5/29/2008 68988 2/2/1995 68988 1/2/1998 69183 3/18/1983 69183 10/21/2013 69183 1/19/2000 69183 10/29/2002 69183 4/22/2005 69207 9/4/1991 69278 11/30/2009 69278 5/26/2015 69313 5/22/2017 69313 10/19/2003 69474 10/30/1990 69505 4/26/2005 69505 9/14/1995 69505 12/3/2001 69505 7/30/2009 69553 4/28/1990 69553 6/23/2009 69553 4/15/1995 69709 9/18/2003 69709 5/22/2000 69709 8/5/1989 69709 3/23/2017 69709 10/7/1993 69709 1/9/2011 69961 11/8/1986 69961 8/8/2020 69961 8/17/2000 69961 5/19/1989 70009 8/27/2009 70009 12/5/1988 70157 11/9/1996 70157 12/7/1990 70273 10/19/2008 70317 11/1/2010 70342 10/17/2003 70458 7/20/2012 70527 10/4/2007 70527 8/19/1992 70583 3/6/2022 70916 11/28/2007 71011 9/2/2013 71011 4/5/2012 71023 7/8/2003 71529 11/1/2001 71661 3/8/2010 71661 6/15/1989 71782 5/2/2013 71813 4/10/1986 71869 2/12/2020 71869 12/22/2003 71869 12/2/2010 71869 3/19/2015 71907 12/12/2022 71907 3/24/1994 72635 10/15/2005 72635 3/25/2009 72698 9/1/2014 72735 2/7/2011 72735 4/22/2009 73035 6/19/2008 73035 7/6/1999 73038 10/24/2020 73073 5/6/1995 73073 6/16/1992 73073 9/25/2005 73161 9/2/1993 73427 5/23/2010 73427 2/5/2001 73499 8/8/1985 73499 8/6/2008 73499 5/20/1989 73499 5/8/1984 73499 3/12/2002 73533 9/27/2020 73533 8/14/2014 73533 8/4/2017 73533 8/13/1983 74163 1/8/2018 74585 11/7/1989 74585 10/7/2006 74705 9/23/1995 74705 3/7/2014 74802 3/2/2017 74802 2/19/2007 74825 7/10/2021 75135 6/23/2020 75314 4/18/2010 75915 12/27/2012 75923 7/26/2013 75923 4/10/2002 75923 6/26/1990 75978 2/15/2001 76029 10/17/1989 76045 2/18/2019 76045 6/30/2005 76045 1/12/2009 76045 7/10/1997 76090 6/7/2007 76354 8/10/1982 76488 10/8/1989 76555 6/29/2009 76555 12/16/1988 76555 3/14/2011 76736 10/11/2014 76736 5/9/1983 76736 5/17/2021 76736 12/28/2010 76847 8/31/1984 76847 5/2/2019 76847 8/22/1996 76915 9/7/2002 77017 11/29/1989 77082 9/2/2008 77082 2/5/2008 77082 12/13/1993 77082 2/7/1995 77082 12/12/1999 77612 9/4/2007 77726 4/21/2011 77726 9/25/2018 77726 11/18/1982 77739 10/24/1984 77810 9/29/2012 77954 10/6/1993 77954 10/28/1990 78098 10/31/2021 78098 11/10/2006 78108 5/28/1992 78387 10/27/2001 78387 12/18/2007 78387 2/1/1984 78522 12/20/1994 78522 12/29/1993 78573 11/11/2017 78573 2/8/1990 78631 8/25/2015 78631 1/22/2008 78665 9/22/2022 78665 6/26/1995 78665 4/30/1995 78714 1/26/2021 78714 2/29/2020 78714 12/30/1989 78941 10/30/1984 79336 1/9/1998 79336 6/30/2007 79336 3/16/2009 79482 7/23/1998 79482 4/15/2009 79482 2/23/2023 79571 5/8/2014 79571 10/29/1988 79597 7/21/1988 79597 6/22/1993 79614 11/21/1994 79614 5/14/2015 79614 6/24/1982 79614 6/7/1982 79614 12/15/2012 79712 11/19/1986 79712 12/4/1993 79810 7/29/1987 79859 11/10/1985 79859 4/14/1997 79859 12/7/1986 79892 6/15/2012 79892 4/2/1998 79892 8/28/2004 79921 9/25/2020 79921 2/3/1989 79921 6/4/2020 79921 10/3/1985 80254 3/5/2023 80254 8/17/1998 80254 10/25/1994 80254 12/14/1984 80265 10/4/2002 80265 4/6/2005 80265 2/18/2016 80265 11/14/1988 80309 10/1/1994 80309 7/13/2011 80309 2/20/2002 80633 3/6/2023 80633 4/1/1988 80941 5/8/1998 80941 6/15/2019 81057 7/7/1993 81057 3/24/1997 81244 9/17/1989 81356 7/31/2015 81356 5/13/2005 81356 10/5/2010 81380 4/21/2012 81801 11/27/1984 81801 12/8/2005 81801 9/30/1995 81801 7/17/2004 81801 4/5/2004 82044 5/7/2009 82044 2/3/2006 82107 5/25/2002 82107 1/24/1995 82294 6/12/1994 82560 7/16/1997 82560 6/14/1987 82586 5/15/1998 82586 5/5/2019 82586 10/15/1991 82586 5/4/1999 82646 7/26/1997 82772 9/23/2015 82772 4/1/2005 82772 1/4/2013 82772 5/23/1982 82791 4/5/2022 82791 10/27/2011 82791 1/30/2004 82826 9/12/2006 82826 4/30/1982 82955 8/16/1984 82955 3/15/2019 82964 6/1/2003 83056 4/27/1984 83142 6/23/1987 83286 1/26/2008 83286 1/5/2012 83286 10/7/1984 83407 3/11/1984 83651 3/12/1999 83780 9/7/2007 83848 10/3/2011 83848 7/22/2018 83867 5/20/2002 83867 11/3/2002 83867 4/11/2019 83867 6/1/2016 83867 9/10/2012 83867 3/1/1998 83895 9/29/2016 84083 1/16/1989 84083 3/25/2017 84139 7/18/1997 84223 6/11/1989 84307 11/18/2008 84359 8/19/2018 84443 8/25/2001 84566 1/26/2018 84628 4/11/1993 84628 8/31/2014 84628 4/11/1990 84729 2/17/1998 84729 11/19/2010 84729 5/16/2016 84866 9/19/2019 84866 4/29/1997 85104 12/28/2011 85104 12/24/1990 85104 3/26/2020 85104 8/30/2007 85104 4/18/2006 85104 9/21/1987 85104 2/15/2012 85111 5/14/1986 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2/23/2002 95199 5/18/2008 95217 1/30/1999 95304 12/22/2003 95304 4/11/1995 95304 4/5/2009 95304 4/22/1993 95436 9/11/2012 95436 12/10/2017 95436 3/15/2002 95436 6/9/2021 95436 9/14/2016 95485 4/12/1995 95485 6/28/2022 95485 8/28/2021 95485 12/19/2019 95532 6/28/1996 95532 3/25/1983 95559 11/8/1995 95559 2/25/2010 95561 11/5/2007 95561 8/13/1995 95581 12/30/1987 95590 7/18/2015 95600 1/21/1999 95600 12/25/2009 95600 1/8/2004 95600 1/8/1986 95827 7/24/1998 95827 7/29/1991 95827 9/7/2003 95827 6/12/2018 95827 3/7/1983 96027 2/10/1984 96187 5/19/1995 96187 6/8/1986 96194 12/11/1983 96194 8/12/1995 96194 7/18/2012 96194 9/6/2015 96194 5/1/1992 96248 8/2/1983 96357 4/3/1996 96421 3/19/2021 96487 8/25/1994 96487 8/8/1989 96487 6/28/1984 96765 9/15/1995 96789 10/22/2019 96828 3/4/1999 96828 4/20/2002 96828 10/13/1986 96828 4/22/2012 96828 12/10/2022 96828 8/12/2001 97069 2/27/1991 97069 3/2/1995 97619 1/17/2012 97756 12/11/2005 97756 6/2/2017 97756 2/17/2003 97811 10/10/2010 97811 8/4/1983 97811 5/7/2021 97815 1/2/1994 97815 11/28/2020 97860 2/26/2012 97920 10/9/2006 98014 1/30/1997 98053 4/3/1984 98053 9/14/2009 98053 4/17/1983 98073 6/20/1989 98073 12/15/2019 98073 7/20/2014 98073 7/29/2008 98094 7/7/1996 98491 10/15/2016 98559 7/14/2012 ; </CODE></PRE> Thu, 12 Aug 2021 23:59:40 GMT https://communities.sas.com/t5/SAS-Programming/don-t-understand-this-one-line-in-my-code/m-p/761319#M240891 axescot78 2021-08-12T23:59:40Z https://communities.sas.com/t5/SAS-Programming/don-t-understand-this-one-line-in-my-code/m-p/761320#M240892 <P>It's only going to include rows in the results set where the dates are greater in the second table than the first.</P> <P>&nbsp;</P> <PRE><CODE class=" language-sas">from fake_data a, fake_data b where a.pat_id = b.pat_id and b.visit_date &gt; a.visit_date and intck('day', b.visit_date, a.visit_date) &lt; 366;</CODE></PRE> <P>It's looking for visits&nbsp;<EM>after&nbsp;</EM>the first visit but within one year of the first visit.&nbsp; In other words, it's looking to gather the rows of patient who visited more than once in a rolling year period.</P> <P>&nbsp;</P> <P>By the way, if you'll notice, the join is between two ... well sort of virtual instances of the same table.&nbsp; This is a real cool feature of SQL that you can join tables to themselves.</P> <P>&nbsp;</P> <P>Jim</P> Fri, 13 Aug 2021 00:22:29 GMT https://communities.sas.com/t5/SAS-Programming/don-t-understand-this-one-line-in-my-code/m-p/761320#M240892 jimbarbour 2021-08-13T00:22:29Z https://communities.sas.com/t5/SAS-Programming/don-t-understand-this-one-line-in-my-code/m-p/761324#M240896 <P>I think you've got your start and end dates mixed up. This might work better:</P> <PRE><CODE class=" language-sas">proc sql; create table cares_count as select distinct a.pat_id, 1 as flag from fake_data a, fake_data b where a.pat_id = b.pat_id and 0 &lt; intck('day', a.visit_date, b.visit_date) &lt; 366; quit;</CODE></PRE> Fri, 13 Aug 2021 01:02:39 GMT https://communities.sas.com/t5/SAS-Programming/don-t-understand-this-one-line-in-my-code/m-p/761324#M240896 SASKiwi 2021-08-13T01:02:39Z https://communities.sas.com/t5/SAS-Programming/don-t-understand-this-one-line-in-my-code/m-p/761325#M240897 that's what I thought it was doing but I thought you would have to specify to compare the earliest date such as with a min() function. thanks! Fri, 13 Aug 2021 01:03:46 GMT https://communities.sas.com/t5/SAS-Programming/don-t-understand-this-one-line-in-my-code/m-p/761325#M240897 axescot78 2021-08-13T01:03:46Z