Home/ Questions/Q 109647
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-11T02:06:08+00:00

I know it’s generally a bad idea to do queries like this: SELECT *

  • 0

I know it’s generally a bad idea to do queries like this:

SELECT * FROM `group_relations`

But when I just want the count, should I go for this query since that allows the table to change but still yields the same results.

SELECT COUNT(*) FROM `group_relations`

Or the more specfic

SELECT COUNT(`group_id`) FROM `group_relations`

I have a feeling the latter could potentially be faster, but are there any other things to consider?

Update: I am using InnoDB in this case, sorry for not being more specific.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. If the column in question is NOT NULL, both of your queries are equivalent. When group_id contains null values, 

    select count(*)

    will count all rows, whereas

    select count(group_id)

    will only count the rows where group_id is not null.

    Also, some database systems, like MySQL employ an optimization when you ask for count(*) which makes such queries a bit faster than the specific one.

    Personally, when just counting, I’m doing count(*) to be on the safe side with the nulls.

    • 0