How do I insert a value into every record in a column of a table?

A statement of type UPDATE - when you have records in the table and want to update them - is done as follows MySQL :

UPDATE nome_tabela SET campo = valor

• The UPDATE statement updates existing row columns in the table with names with new values.
• The SET clause indicates which columns to modify and which values to provide.

In your case, to update the value of all records you simply remove the WHERE clause - used to filter / restrict some records - and then just > query similar to this:

UPDATE categoria SET campo = 3

update categoria set coluna='3' where coluna != '3'

I imagine it to be something like this. This only works on the console or if you disable mysql security because it does not leave for security

Since the field you want to update is called campo :

UPDATE categoria
SET campo = 3

MySQL statement:

UPDATE Categoria
SET Campo = 3

This causes all values in the "Field" column to change to "3". If there is a need to do this for specific lines, a conditional ( WHERE ) is required.

Hug.