The following error might occur if you use multiple instances of INNER JOIN syntax and you reference a table column in the ON clause before that table is referenced by the INNER JOIN:
This error is produced by an SQL procedure similar to the following:
proc sql;
select * from table1
inner join table2
on table3.col1 = table1.col1
inner join table3
on table2.col1 = table1.col1 ;
quit;
Note that the first ON clause contains a reference to TABLE3 before it is introduced as a table to be used in the query. To avoid this problem, be sure to reference the table prior to the INNER JOIN clause.