SQL left join - identify cause of row duplication

[LEINAARE]

Hello,

I am using PROC SQL to perform a left join using four common variables to join one new variable.  The left dataset has 45,370,249 rows.  The right dataset has 14,496,317 rows.  The new table contains 45,370,500 rows.  I would like to identify which records from the right dataset are causing row duplication on the left dataset.  Could anyone offer suggestions?  Below is a copy of my program.

Thanks

proc sql;
	create table medical_1217 as
	select a.*, b.provspec
	from medical_1217_icd10 a
	left join provspec_merge b
	on a.orsid = b.orsid
	and a.recordid = b.recordid
	and a.log = b.log
	and a.file_type = b.file_type;
quit;

[Reeza · Accepted solution]

Usually quickest way is to count by your ID groups in each data set and find one that's duplicated multiple points and trace it.

[LEINAARE]

Thank you for your help.