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- No Correlation
Select Name
From emp
sal = ( Select avg(sel) from emp )
- Compute and Reuse.
- Select Name
from Emp X
where salary > ( Select Salary avg(sal) from emp where empno = x.manager);
- frequent reevalution.
- Order access on correlation var value => no reevalution, use prev.
- Also : memoing schemes
DBMS
1999-03-12