I want to know which one is better indexed in the below 2 examples:
Below query has index(category_id,date_created )
EXPLAIN SELECT postid
FROM posts
WHERE category_id =53
AND approval = ‘yes’
ORDER BY date_created DESC
LIMIT 0 , 10
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE posts index category_id date_created 9 NULL 199 Using where
Below query has one index(date_created ), removed index (category_id)
EXPLAIN SELECT postid
FROM posts
WHERE category_id =53
AND approval = ‘yes’
ORDER BY date_created DESC
LIMIT 0 , 10
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE posts index NULL date_created 9 NULL 10 Using where
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Which one among the two is better indexing ? The difference is rows_examined. Should I be concerned about query execution time as its not much differnce in above two or the rows_examined?
Please guide me. Thanks.