how to give a default value to a column in sql code example

Example 1: how to add default constraint in mysql

ALTER TABLE "name_table" ALTER "name_column" 
SET DEFAULT value_default;

Example 2: default number in sql

//Sql Server

//Add a table 
ALTER TABLE clients ADD Points INT DEFAULT 0
//Edit an existing table
ALTER TABLE clients ADD CONSTRAINT points DEFAULT 0 FOR Points

Example 3: set default column value sql

Name Varchar(255) default "Fred"