Does MySQL Update a Column with an Identical Value?

MySQL Column Update with Identical Value

When updating a table in MySQL, it's important to consider the behavior of the database when setting a column to a value it already possesses.

For example, let's say we have the following table:

user
------------------
| user_id | user_name |
|---------|-----------|
| 1        | John      |
| 2        | Joseph    |
| 3        | Juan      |

If we execute the following query:

UPDATE `user` SET user_name = 'John' WHERE user_id = 1

Will MySQL overwrite the existing value of 'John' in the first row or ignore the update since it's the same content?

Answer:

• According to the MySQL manual for the UPDATE statement, "If you set a column to the value it currently has, MySQL notices this and does not update it."

Therefore, when running the query above, MySQL will recognize that the value you're attempting to apply is identical to the current value for the 'user_name' column and will not update the database.

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