find function finds the position of a string within a main string. Eg w=find('SAS','A'); returns 2 to be the value of the i.e. location of 'A'. In your example you are getting all the string before 'NP'. Need to look at an example of why the subtraction of -2 is happening. "The FIND function searches string for the first occurrence of the specified substring, and returns the position of that substring. If the substring is not found in string, FIND returns a value of 0."   ... View more

Eventhough mathematically they are the same how sas is handling the precision might be different. Round both values to a fixed decimal say six positions and then compare. Format statement is display only. It does not change the original value. Use round function instead ... View more

In the first data step you have if address_lin = address1; remove that line. Change the condition <50 to less than 2 ... View more

Please try scantext option. SCANTEXT applies to columns containing text. If SCANTEXT=YES, then SAS will scan the column for the longest string, and uses its length as the column width. ... View more

Adding a new variable does not change the result any way unless there is a business logic associated with it or the column is on both datasets. See my earlier response. You get your desired result using a data step merge, but this is wrong. ... View more

What you showed in the output is this. @mkeintz , @newsas007 please notice this response   data A; informat id 3. date_a mmddyy10. Drug_list $200.; input id date_a Drug_list; format id 3. date_a mmddyy10. Drug_list $200.; cards; 1 1/2/2018 Afatinib,Cetuximab,Dacomitinib,Erlotinib,Gefitinib,Lapatinib,Necitumumab,Osimertinib,Panitumumab 1 2/10/2019 Cetuximab,Panitumumab 2 3/3/2019 Binimetinib,Cetuximab,Cobimetinib,Idelalisib,Panitumumab,Trametinib 3 1/2/2018 Alpelisib,Everolimus,Temsirolimus 4 2/10/2019 Bosutinib,Dasatinib,Everolimus,Temsirolimus 5 3/3/2019 Afatinib,Cetuximab,Dacomitinib,Erlotinib,Gefitinib,Lapatinib,Necitumumab,Osimertinib,Panitumumab 6 1/2/2018 Binimetinib,Cetuximab,Cobimetinib,Idelalisib,Panitumumab,Trametinib 7 2/10/2019 Alpelisib,Everolimus,Temsirolimus ;;; proc sort; by id; run; data B; informat id 3. date_b mmddyy10. Drug $20.; input id date_b Drug; format id 3. date_b mmddyy10. Drug $200.; cards; 1 2/01/2018 Panitumumab 1 3/02/2019 Binimetinib 1 3/28/2019 Cetuximab 2 3/23/2019 Trametinib 2 3/25/2019 Temsirolimus 3 2/01/2018 Alpelisib 5 3/21/2019 Dacomitinib 4 3/01/2019 Everolimus 6 1/17/2018 Idelalisib 7 3/02/2019 Temsirolimus ;;; proc sort; by id; run; data c; merge b a; by id; if findw( drug_list,strip(drug),',') = 0 then drug_list=''; run; Which might be wrong as you get this warning in the log     NOTE: MERGE statement has more than one data set with repeats of BY values. NOTE: There were 10 observations read from the data set WORK.B. NOTE: There were 8 observations read from the data set WORK.A. NOTE: The data set WORK.C has 10 observations and 5 variables. NOTE: DATA statement used (Total process time): real time 0.01 seconds cpu time 0.01 seconds instead the result should be  Proc sql; Create table c2 as select a.date_a,a.drug_list, b.date_b, b.Drug,b.id from a a right join b b on a.id=b.id and findw( a.drug_list,strip(b.drug),',') > 0 and (b.date_b); Quit; date_a Drug_list date_b Drug id 1/2/2018 Afatinib,Cetuximab,Dacomitinib,Erlotinib,Gefitinib,Lapatinib,Necitumumab,Osimertinib,Panitumumab 2/1/2018 Panitumumab 1 1/2/2018 Afatinib,Cetuximab,Dacomitinib,Erlotinib,Gefitinib,Lapatinib,Necitumumab,Osimertinib,Panitumumab 3/28/2019 Cetuximab 1 2/10/2019 Cetuximab,Panitumumab 2/1/2018 Panitumumab 1 2/10/2019 Cetuximab,Panitumumab 3/28/2019 Cetuximab 1     3/2/2019 Binimetinib 1 3/3/2019 Binimetinib,Cetuximab,Cobimetinib,Idelalisib,Panitumumab,Trametinib 3/23/2019 Trametinib 2     3/25/2019 Temsirolimus 2 1/2/2018 Alpelisib,Everolimus,Temsirolimus 2/1/2018 Alpelisib 3 2/10/2019 Bosutinib,Dasatinib,Everolimus,Temsirolimus 3/1/2019 Everolimus 4 3/3/2019 Afatinib,Cetuximab,Dacomitinib,Erlotinib,Gefitinib,Lapatinib,Necitumumab,Osimertinib,Panitumumab 3/21/2019 Dacomitinib 5 1/2/2018 Binimetinib,Cetuximab,Cobimetinib,Idelalisib,Panitumumab,Trametinib 1/17/2018 Idelalisib 6 2/10/2019 Alpelisib,Everolimus,Temsirolimus 3/2/2019 Temsirolimus 7   ... View more

data A; informat id 3. date_a mmddyy10. Drug_list $200.; input id date_a Drug_list; format id 3. date_a mmddyy10. Drug_list $200.; cards; 1 1/2/2018 Afatinib,Cetuximab,Dacomitinib,Erlotinib,Gefitinib,Lapatinib,Necitumumab,Osimertinib,Panitumumab 1 2/10/2019 Cetuximab,Panitumumab 2 3/3/2019 Binimetinib,Cetuximab,Cobimetinib,Idelalisib,Panitumumab,Trametinib 3 1/2/2018 Alpelisib,Everolimus,Temsirolimus 4 2/10/2019 Bosutinib,Dasatinib,Everolimus,Temsirolimus 5 3/3/2019 Afatinib,Cetuximab,Dacomitinib,Erlotinib,Gefitinib,Lapatinib,Necitumumab,Osimertinib,Panitumumab 6 1/2/2018 Binimetinib,Cetuximab,Cobimetinib,Idelalisib,Panitumumab,Trametinib 7 2/10/2019 Alpelisib,Everolimus,Temsirolimus ;;; data B; informat id 3. date_b mmddyy10. Drug $20.; input id date_b Drug; format id 3. date_b mmddyy10. Drug $200.; cards; 1 2/01/2018 Panitumumab 1 3/02/2019 Binimetinib 1 3/28/2019 Cetuximab 2 3/23/2019 Trametinib 2 3/25/2019 Temsirolimus 3 2/01/2018 Alpelisib 5 3/21/2019 Dacomitinib 4 3/01/2019 Everolimus 6 1/17/2018 Idelalisib 7 3/02/2019 Temsirolimus ;;; Proc sql; Create table c as select a.*, b.date_b, b.Drug from a a, b b Where index( a.drug_list,strip(b.drug)) > 0; Quit; Got the order of values wrong. ... View more

You can use a proc sql join Proc sql; Create table c as select a.*, b.* from a a, b b Where index(b.drug, a.drug_list) >0; Quit; ... View more