What Is TIMESTAMP? - MySQL FAQs - Introduction to SQL Date and Time Handling

A TIMESTAMP data type allows you to record a date and time like DATETIME data type. But it has some interesting features when used on a table column:

• The first TIMESTAMP column in a table will be assigned with the current date and time, if it is not listed in an INSERT statement.
• The first TIMESTAMP column in a table will be assigned with the current date and time, if it is not listed in an UPDATE statement.
• If a TIMESTAMP column is assigned with NULL, the current date and time will be persisted to this column.
• You can turn off the default current date and time on INSERT by defining the column with "DEFAULT 0".

• The tutorial exercise below provides you 2 equivalent ways to create a TIMESTAMP column:

  CREATE TABLE links (lastDate TIMESTAMP);
  
  CREATE TABLE links (lastDate TIMESTAMP 
     DEFAULT CURRENT_TIMESTAMP
     ON UPDATE CURRENT_TIMESTAMP);