Does MySQL Update Unchanged Columns During Updates?

Does MySQL Overwrite Unchanged Columns During Updates?

When updating a MySQL table, as the example provided demonstrates:

user_id	user_name
1	John
2	Joseph
3	Juan

If the following query is executed:

<code class="sql">UPDATE `user` SET user_name = 'John' WHERE user_id = 1</code>

Will MySQL modify the "user_name" column despite the intended change being identical to the existing value?

MySQL's Approach to Unchanged Column Values

According to the MySQL documentation for the UPDATE statement:

"If you set a column to the value it currently has, MySQL notices this and does not update it."

In our case, MySQL recognizes that the intended "user_name" value for user_id 1 is identical to the current value. Therefore, MySQL will refrain from modifying the database.

Thus, the query will execute without altering the table data, as MySQL detects that no actual changes are necessary for the specified column.

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