yyyy'-'MM'-'dd'T'HH':'mm':'ss - What is the meaning of 'T' here?

Question

What is the meaning of T in this datetime pattern ?

yyyy\'-\'MM\'-\'dd\'T\'HH\':\'mm\':\'ss 2011-06-14T04:12:36

Answer 1

It's from ISO 8601 which specifies a standard timestamp format:

The character [T] shall be used as time designator to indicate the start of the representation of the time of day component in these expressions.