Question

i have a table similar this

one
two
three
four
five 
six
seven

i need a function for this table with similar output

one-two-tree
two-three-four
three-four-five
...

Wikipedia page on n-gram

Answer 1

Tested in MySQL. First creating the data:

create table words(id integer auto_increment primary key, text varchar(255));
insert into words (text) values ('one');
insert into words (text) values ('two');
insert into words (text) values ('three');
insert into words (text) values ('four');
insert into words (text) values ('five');
insert into words (text) values ('six');
insert into words (text) values ('seven');

The query:

select
    t1.text as tx1,
    t2.text as tx2,
    t3.text as tx3
from
    words as t1,
    words as t2,
    words as t3
where
    (t1.id + 1) = t2.id
    and
    (t2.id + 1) = t3.id
;

It relies on word IDs being in sequence. A string concatenation function can be used to combine 3 columns into one.

select
    concat(t1.text, '-',
           t2.text, '-',
           t3.text)
    as trigram
from
    words as t1,
    words as t2,
    words as t3
where
    (t1.id + 1) = t2.id
    and
    (t2.id + 1) = t3.id
;