mysql UPDATE statement – overhead for same values?

by

No, MySQL is smart and won’t be slower. Don’t go through the trouble of checking for that, MySQL will do it for you.

If you set a column to the value it currently has, MySQL notices this and does not update it. No write action is performed. (Source)

BUT,

MySQL can use the WHERE-clause on the column-to-update to determine which index to use (and thus which rows to examine), in which case it might speed up your UPDATE-operation. If your column is indexed, do include it.

More Related Contents:

  1. Cakephp Career Database Design
  2. Write the function using plsql [closed]
  3. How do you join on the same table, twice, in mysql?
  4. Throw an error preventing a table update in a MySQL trigger
  5. MySQL and GROUP_CONCAT() maximum length
  6. What data type to use for hashed password field and what length?
  7. MySQL pagination without double-querying?
  8. MySQL convert date string to Unix timestamp
  9. How to speed up SELECT .. LIKE queries in MySQL on multiple columns?
  10. MySql Table Insert if not exist otherwise update
  11. How do I select an entire row which has the largest ID in the table?
  12. MySQL error 1064 syntax but everything seems fine
  13. MySQL/MariaDB – order by inside subquery
  14. How to run SQL script in MySQL?
  15. My MySQL trigger doesn’t work, simple syntax, not complicated
  16. Removing MySQL 5.7 Completely [closed]
  17. How to optimize COUNT(*) performance on InnoDB by using index
  18. script to convert mysql dump sql file into format that can be imported into sqlite3 db
  19. Sum results of a few queries and then find top 5 in SQL
  20. ERROR 1148: The used command is not allowed with this MySQL version
  21. Too many auto increments with ON DUPLICATE KEY UPDATE
  22. SQL (MySQL) vs NoSQL (CouchDB) [closed]
  23. Select by Month of a field
  24. MySQL Illegal mix of collations
  25. MySQL GROUP BY age range including null ranges
  26. MySQL update statement to store ranking positions
  27. Best tool for synchronizing MySQL databases [closed]
  28. MySQL scripts in docker-entrypoint-initdb are not executed
  29. How to import a csv file into MySQL workbench?
  30. MySQL: SELECT from another server

Leave a Comment