Name
PER-07: Optimize conditional structures
Synopsis
The performance of IF
and
CASE
statements is highly
dependent on the number of comparisons that the statement must
execute. The number of comparisons can be optimized in two
ways:
By placing the comparisons that are most frequently true earliest in the set of comparisons, you reduce the number of comparisons that must be executed.
If any comparison is repeated in multiple expressions within the
CASE
orIF
statement, you can extract that comparison and “nest” multipleCASE
orIF
statements. The inner comparisons need only be executed when the outer comparison evaluates to TRUE.
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