Does indexing a date column improve performance?

Question

I have a table with millions of rows where one of the columns is TIMESTAMP and against which I often choose for date ranges. Will it improve the performance of anyone to index this column, or will it not provide any noticeable improvements?

EDIT:

So, I indexed the TIMESTAMP column. Next request select count(*) from interactions where date(interaction_time) between date('2013-10-10') and date(now())

Takes 3.1 seconds.

The interaction table contains more than 3 million records.

The above query gives the result ~ 976k

Does this seem like a reasonable amount of time to complete this task?

Answer 1

, :

• .

• -, , , sargable, . , . :

  WHERE interaction_time >= '2013-10-10' 
    AND interaction_time < (CURRENT_DATE + INTERVAL 1 DAY)
  

Answer 2

, :

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.

Answer 3

select count(*) from interactions where date(interaction_time) between date('2013-10-10') and date(now())

:

• interaction_time date(interaction_time)
• , interaction_time
• () '2013-10-10' not date('2013-10-10')

# 1, , , .

Answer 4

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Answer 5

Adding an index to a date column definitely improves performance.

My table has 11 million rows, and the query to fetch rows that were updated to a specific date took the following time according to the conditions:

Without index: ~ 2.5 s

With index: ~ 5 ms