Timeline for SQL optimization
Current License: CC BY-SA 4.0
8 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 3, 2020 at 6:01 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Jan 7, 2020 at 22:23 | history | edited | CommunityBot |
added [query-performance] to 2412 questions - Shog9 (Id=1924)
|
|
| Oct 29, 2018 at 17:11 | answer | added | Rick James | timeline score: 0 | |
| Oct 29, 2018 at 16:43 | history | edited | ricardo | CC BY-SA 4.0 |
50% done
|
| Oct 29, 2018 at 14:37 | comment | added | Kondybas |
You are right, mysql do not use indexes for any function. In case of SUBSTRING() the proper index should contain all possible substrings for each string stored in the field. That would drive to the huge overhead for storage and computation and for some cases indexed search would be slower that non-indexed. That is why you have to refactor the database and exclude as possible any functions from JOIN/GROUP/ORDER/WHERE clauses if you need optimization.
|
|
| Oct 29, 2018 at 13:30 | history | edited | ricardo | CC BY-SA 4.0 |
add comment to sql
|
| Oct 29, 2018 at 13:21 | history | edited | Paul White♦ |
edited tags
|
|
| Oct 29, 2018 at 13:01 | history | asked | ricardo | CC BY-SA 4.0 |