Hi!!
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:
proc sql;
delete
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?
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.
I would like to use data step ,when the table is very very big. For you scenario, I recommend Hash Table.
Xia Keshan
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