How to use SUBSTRING using REGEXP in MySQL
This would need to use the LOCATE and SUBSTRING syntax to get the information out of the string.
The basic locate syntax you would need is explained here.
LOCATE (search str, str, [position])

search str = A string which will be searched for.
str =A string which is going to be searched.
position (optional)= Position from where (within the second argument) the searching will start .

While the substring function you need is explained here
SUBSTRING(str, pos, len)

str=  A string.
pos=  Starting position.
len=  Length in characters.

The easier way of viewing this is to think of substring as the following
SUBSTRING(str FROM pos FOR len)
The sytax I used to get the second word is below, I took advantage of the spaces that are constantly around the second word you are trying to extract.
declare @String varchar(50) ='Lorem D9801 ipsum dolor sit amet'

SUBSTRING
(
@String,
LOCATE(' ', @String),
LOCATE(' ', @String, (LOCATE(' ', @String) + 1)) - LOCATE(' ', @String)
)