CONVERT()  function is basically used to converts an expression of one data type to another data type. This function display date/time data in different formats.

Syntax:-
CONVERT(data_type(length),expression,style)

data_type(length):- It is used to specifies the target data type.

expression:- It is used to specifies the value to be converted.

style:- It is used to specifies the output format for the date/time.

Example 1:-
     In this example we take a style value 108 which defines the following format:

hh:mm:ss

Now use the above style in the following query:

select convert(varchar(20),GETDATE(),108)

Output:-

15:05:30

Example 2:-

In this example we use the style value 107 which defines the following format:

Mon dd, yy

Now use that style in the following query:

select convert(varchar(20),GETDATE(),107)

Output:-

September 23, 2016