Is SQL SELECT faster if called in right order?

Question

Assume we have a table:

|   col1   |   col2   |   ....  |  coln   |
-------------------------------------------
|    -     |    -     |    -    |    -    | 
|    -     |    -     |    -    |    -    | 
|    -     |    -     |    -    |    -    | 
-------------------------------------------

a query where the columns are ordered:

$query1 = "SELECT col1, col2, col3, col4, col5, ..., coln FROM table";

and a query where the columns are unordered:

$query2 = "SELECT col180, col1, col78, col13, col930, col2 FROM table";

Is one of the queries faster than the other? Why would it be faster? Or, why isn't one faster?

Use the query log and check the time ;) I think regardless of its place in the table if you select field by field — ceadreak, Apr 15 '14 at 12:59
no, it should not matter (in most cases :)): http://dba.stackexchange.com/a/33984/27819 — DrCopyPaste, Apr 15 '14 at 13:00
This question is not a duplicate (at least of the stated question) because it does not specify the database. — Gordon Linoff, Apr 15 '14 at 13:20
There is a difference, Similar usecase. http://stackoverflow.com/a/11227902/1008278 — VenomVendor, Apr 15 '14 at 14:12

AhDev · Accepted Answer · 2020-07-18T01:53:36.127

7

It should make a very small impact on performance. Here is a previous answer by spencer7593 that explains in detail:

The order of columns in a table will have a very small impact on performance, as compared to the performance impact of your database design (entities, attributes and relationships), your transaction design and your query design.

edited Jul 18 '20 at 01:53

answered Apr 15 '14 at 13:00

AhDev

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It should be "a very small impact on performance", NOT a noticeable difference!!! – V G Apr 15 '14 at 13:10
^^ What I meant. My apologies. I edited my response. – AhDev Apr 15 '14 at 13:25
While this link may answer the question, it is better to include the essential parts of the answer here and provide the link for reference. Link-only answers can become invalid if the linked page changes. – neubert Apr 15 '14 at 13:40
Very good point @neubert. I have edited the response. Thank you. – AhDev Apr 15 '14 at 13:44

Is SQL SELECT faster if called in right order?

1 Answers1