Can someone give me tips on how to use the substring function - sql

Question

I have a query where the first column display name length the second is title or courtesy I have done those but I'm having trouble with my third column. It is supposed to use substring and display first name initial and last name initial can anyone tell me how to add this function to what I already have?
Here is the query
SELECT 'Your full name is ' + CAST(LEN(FirstName) + LEN(LastName) AS VARCHAR(12)) + ' character(s).' AS [Length of Employee Name],
CASE TitleOfCourtesy WHEN 'Mr.' THEN 'Mister '
WHEN 'mrs. ' THEN 'Miss'
WHEN 'Ms.' THEN 'Miss '
WHEN 'Dr.' THEN 'Doctor '
ELSE '' END + TitleOfCourtesy + LastName AS title
FROM dbo.Employees

Answer 1

(since you used LEN I assume you are using SQL Server)
You mean something like this?
substring(FirstName,1,1) + substring(LastName,1,1)
In general it is like this :
substring(expression, startPosition, lenght)

Answer 2

I would use LEFT() instead of substring.
DECLARE #Employees TABLE (FirstName VARCHAR(25),LastName VARCHAR(25), TitleOfCourtesy VARCHAR(5))
INSERT INTO #Employees
VALUES ('Bob','Brown','Mr.'),
('Olivia','Taylor','M rs.'),
('Grace','Stevens','Ms.'),
('Theodor','Seuss','Dr.');
SELECT 'Your full name is ' + CAST(LEN(FirstName) + LEN(LastName) AS VARCHAR(12)) + ' character(s).' AS [Length of Employee Name],
CASE Replace(TitleOfCourtesy, ' ','') --Gets rid of any white space
WHEN 'Mr.' THEN 'Mister'
WHEN 'mrs.' THEN 'Miss'
WHEN 'Ms.' THEN 'Miss'
WHEN 'Dr.' THEN 'Doctor'
ELSE ''
END + ' ' + LastName AS title,
CONCAT(LEFT(FirstName,1),'.',LEFT(LastName,1),'.') AS Initials
FROM #Employees
Results:
Length of Employee Name title Initials
-------------------------------------------- -------------------------------- --------
Your full name is 8 character(s). Mister Brown B.B.
Your full name is 12 character(s). Miss Taylor O.T.
Your full name is 12 character(s). Miss Stevens G.S.
Your full name is 12 character(s). Doctor Seuss T.S.