nerdexam
Oracle

1Z0-883 · Question #45

Consider the following: Mysql> EXPLAIN SELECT FROM City WHERE Name = Jacksonville' AND CountryCode = USA' \G **************************** 1. row ***************************** Id: 1 Select_type…

The correct answer is D. It shows how many bytes will be used from each index row. See the full explanation below for the reasoning.

Question

Consider the following:

Mysql> EXPLAIN SELECT * FROM City WHERE Name = Jacksonville' AND CountryCode = USA' \G ******************************** 1. row ******************************** Id: 1 Select_type: SIMPLE Table: City Type: ref Possible_keys: name_country_index Key: name_country_index Ref: const, const Rows: 1 Extra: Using where Which statement best describes the meaning of the value for the key_len column?

Options

  • AIt shows the total size of the index row.
  • BIt shows how many columns in the index are examined.
  • CIt shows the number of characters indexed in the key.
  • DIt shows how many bytes will be used from each index row.

How the community answered

(29 responses)
  • A
    7% (2)
  • B
    3% (1)
  • C
    17% (5)
  • D
    72% (21)

Community Discussion

No community discussion yet for this question.

Full 1Z0-883 Practice