What is true about non-equijoin statement performance? (Choose two.)
What is true about non-equijoin statement performance? (Choose two.)
Table aliases can improve performance by making queries more readable and easier to parse, which can reduce the time spent on parsing the query. The join syntax used typically does not make a significant difference in performance because modern SQL optimizers handle both Oracle and SQL:1999 compliant ANSI join syntaxes effectively.
D. Table aliases can improve performance. E. The join syntax used makes no significant difference to performance.
D. Table aliases can improve performance. Table aliases can improve performance by reducing the amount of parsing needed to execute the query. C. The Oracle join syntax performs better than the SQL:1999 compliant ANSI join syntax in Oracle 18c. Oracle's join syntax can result in better performance in certain scenarios as it allows the optimizer to understand the join order and access paths more effectively. Therefore, options C and D are correct. Options A, B, and E are incorrect.
A B incorrect because Oracle Between is converted to >= <= C Is arguable D is not true, you don't find a book saying table alias can improve performance. E is arguable C E to answer this poorly designed question
D E are correct
I read that aliases do indeed improve performance, ex. when you order by a column, the parser doesn't need to check all the tables in the query, to find which one the column belongs to. Can anyone confirm this?
D. Table aliases can improve performance. E. the difference related to performance that can be experimented between the two join syntax is minimum since Oracle optimizes internally both manners in a similar way
C and D is true. C is true because oracle Join does perform better. D is true. Table aliases improve the I/O. Refer: https://docs.oracle.com/middleware/1221/bip/BIPDM/best_practices.htm E is false. It does affect performance. Refer: https://docs.oracle.com/cd/F49540_01/DOC/server.815/a67781/c20c_joi.htm
Table alias makes it easy for the parser to look up the columns in their respective tables. "Join" or "Where T1.id=T2.id" conditions have no difference in performance, though join is recommended to be used as the new syntax.
I vote for answers C and E. To be honest, I don't know how good they are, so vague are their contents... I just know that answers A, B and C are wrong. So I vote by elemination.
C and E correct. https://stackoverflow.com/questions/34676965/is-there-a-performance-improvement-when-using-join-vs-a-where-clause
C D E are all correct it seems https://www.examtopics.com/discussions/oracle/view/10257-exam-1z0-071-topic-1-question-253-discussion/
Table aliases can improve performance: Table aliases can potentially improve performance by making the query more readable and reducing the length of the query statements. They can also help to avoid ambiguity when referencing columns from multiple tables. However, the improvement in performance is not directly related to the use of table aliases but rather to the improved readability and maintainability of the query.
C AND E, fundamental NATURAL JOIN performance, Alias table, less memory disc not performance in execution.
D/E Are good, because if you use alianses you say to Oracle where to find.
I disagree with D, table alias does not improve performance. Alias is often used to make it more readable.