Oracle Performance Optimization Operations Ten: Decomposing complex queries and substituting constants for variables

For complex where condition combinations, where contains multiple indexed fields, consider the use of if statements to discuss the situation;

At the same time, remove unnecessary external parameter conditions, reduce complexity, in order to use different fields on the index.

Continue with the example of Oracle performance optimization Operation IX for

Where (Disposalcourseflag < V_disposalcourseflag) or (V_disposalcourseflag is null) and .... The query,

(Here V_disposalcourseflag is an input variable, the value range may be [null,0,1,2,3,4,5,6,7]), you can consider the situation with the IF statement for discussion.

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Oracle Performance Optimization Operations Ten: Decomposing complex queries and substituting constants for variables