Insert the same fixed value into multiple rows

Question

I've got a table with a column, lets call it table_column that is currently null for all rows of the table. I'd like to insert the value "test" into that column for all rows. Can someone give me the SQL for this?

I've tried INSERT INTO table (table_column) VALUES ("test"); but that only populates that last row. How do I do all of the rows at once?

Answer 1

You're looking for UPDATE not insert.

UPDATE mytable SET    table_column = 'test'; 

UPDATE will change the values of existing rows (and can include a WHERE to make it only affect specific rows), whereas INSERT is adding a new row (which makes it look like it changed only the last row, but in effect is adding a new row with that value).

Answer 2

This is because in relational database terminology, what you want to do is not called "inserting", but "UPDATING" - you are updating an existing row's field from one value (NULL in your case) to "test"

UPDATE your_table SET table_column = "test"  WHERE table_column = NULL  

You don't need the second line if you want to update 100% of rows.