Oracle
1Z0-883 · Question #107
1Z0-883 Question #107: Real Exam Question with Answer & Explanation
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Question
Consider the query: Mysql> SET @run = 15; Mysql> EXPLAIN SELECT objective, stage, COUNT (stage) FROM iteminformation WHERE run=@run AND objective='7.1' GROUP BY objective,stage ORDER BY stage; The iteminformation table has the following indexes; Mysql> SHOW INDEXES FROM iteminformation: This query is run several times in an application with different values in the WHERE clause in a growing data set. What is the primary improvement that can be made for this scenario?
Exhibit
Options
- AExecute the run_2 index because it has caused a conflict in the choice of key for this query.
- BDrop the run_2 index because it has caused a conflict in the choice of key for this query.
- CDo not pass a user variable in the WHERE clause because it limits the ability of the optimizer to use indexes.
- DAdd an index on the objective column so that is can be used in both the WHERE and GROUP BY operations.
- EAdd a composite index on (run,objective,stage) to allow the query to fully utilize an index.
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