11-14-2014 12:02 PM
I have two tables:
table1 - 10,000,000 rows
Key: cd1, cd2, cd3, cd4
table2 - 30,000 rows
Key: cd1, cd2
And I want to run the sql below:
from table1 a
where exists (select 1 from table2 b where a.cd1=b.cd1 and a.cd2=b.cd2)
This sql took more than three hours and did not finish.
table1 and table2 are SAS tables.
Does anyone have any tips on how to optimize this SQL?
11-14-2014 01:12 PM
optimizing.... then do not uses SQL.
SQL is designed to have the machine decide. When that decisions are not as wanted the human brain should do his work.