Fetch first character of each word in sqlite3 string - sqlite

Question

In sqlite3 table we have names like as below.
Monty Python
Luther Blissett
Rey maR EsteBaN
Monty Cantsin
Geoffrey Cohen
Karen Eliot
Poor Konrad
I need a query to fetch the character from the database.
Initially I need a query that should fetch first letter of every word in a string. In above example it should display M, P, L, B, R, E, C, G, K
Suppose if a user selects C after the above query, then it should fetch next possible characters of Cantsin and Cohen i.e A and O.
Please provide any inputs on how the solution can be arrived?

Answer 1

Solution below would work if only first name is taken to count.
Consider data:
sqlite> SELECT name FROM COMPANY;
Paul Allen
Mark
Monty Python
Luther Blissett
Monty Cantsin
For 1st query:
sqlite> SELECT distinct substr(name,1,1) FROM COMPANY;
P
M
L
And later for 2nd output try below algorithm:
if you have 1 character input then use substr (name, 2,1)
if you have 2 characters input then use substr (name, 3,1)
.. generally : if x is number of characters input and y is number of character output expected, try substr (name, x+1, y)
sqlite> SELECT distinct substr(name,2,1) FROM COMPANY where name like 'M%';
a
o
sqlite> SELECT distinct substr(name,3,1) FROM COMPANY where name like 'Ma%';
r
If others words also need to be considered for search, replace table name with sub queries as below.
SELECT distinct substr(name,2,1) FROM
(
select name from company where name like 'A%' -- counts for first word
UNION
select name from company where name like '% A%' -- counts for words that start with space
);
Please note that above queries will only return the characters of first word, though the match is for all words it would consider first name as source to fetch characters.