update table column in mysql code example

Example 1: alter table add column

ALTER TABLE table
ADD COLUMN column VARCHAR (255) NOT NULL AFTER column;

Example 2: mysql update add to existing value

mysql> UPDATE tableName SET sometotal = sometotal+10 WHERE Id = 4;

Example 3: alter table mysql

ALTER TABLE contacts
  ADD last_name varchar(40) NOT NULL
    AFTER contact_id,
  ADD first_name varchar(35) NULL
    AFTER last_name;

Example 4: update table mysql

-- Things in brackets are optional
-- IGNORE modifier updates rows even if errors occur (ie: the rows that cause errors are simply not updated)
UPDATE [IGNORE] table_name 
SET 
    column_name1 = expr1,
    column_name2 = expr2,
    ...
[WHERE 
    condition]; -- WHERE tells us which rows to update based on said condition

Example 5: update column mysql with alter

ALTER TABLE table_name
  MODIFY column_name column_definition
    [ FIRST | AFTER column_name ];