Question

How do I UPDATE a column in a MySQL-table if and only if a row with a corresponding column “id” exists?

Example of my table:

id | name
---------
1  | NULL
2  | NULL

Example of my data (CSV):

1, Peter
2, Martin
3, Bob

I want Peter and Martin in the table. But I want Bob to be ignored. My query I came up with looks like this:

"UPDATE table SET name = %s WHERE id = %s"

But what would happen while doing:

"UPDATE table SET name = 3 WHERE id = Bob"

?

Answer 1

It wouldn’t do anything. Your WHERE clause is the conditional. When the condition isn’t met, the update doesn’t occur.