Get previous and next row from rows selected with (WHERE) conditions - sql

Question

For example I have this statement:
my name is Joseph and my father's name is Brian
This statement is splitted by word, like this table:
------------------------------
| ID | word |
------------------------------
| 1 | my |
| 2 | name |
| 3 | is |
| 4 | Joseph |
| 5 | and |
| 6 | my |
| 7 | father's |
| 8 | name |
| 9 | is |
| 10 | Brian |
------------------------------
I want to get previous and next word of each word
For example I want to get previous and next word of "name":
--------------------------
| my | name | is |
--------------------------
| father's | name | is |
--------------------------
How could I get this result?

Answer 1

you didn't specify your DBMS, so the following is ANSI SQL:
select prev_word, word, next_word
from (
select id,
lag(word) over (order by id) as prev_word,
word,
lead(word) over (order by id) as next_word
from words
) as t
where word = 'name';
SQLFiddle: http://sqlfiddle.com/#!12/7639e/1

Answer 2

Why did no-body give the simple answer?
SELECT LAG(word) OVER ( ORDER BY ID ) AS PreviousWord ,
word ,
LEAD(word) OVER ( ORDER BY ID ) AS NextWord
FROM words;

Answer 3

Without subqueries:
SELECT a.word
FROM my_table AS a
JOIN my_table AS b
ON b.word = 'name' AND abs(a.id - b.id) <= 1
ORDER BY a.id

Answer 4

Use Join to get the expected result for SQL Server 2005 plus.
create table words (id integer, word varchar(20));
insert into words
values
(1 ,'my'),
(2 ,'name'),
(3 ,'is'),
(4 ,'joseph'),
(5 ,'and'),
(6 ,'my'),
(7 ,'father'),
(8 ,'name'),
(9 ,'is'),
(10,'brian');
SELECT A.Id , C.word AS PrevName ,
A.word AS CurName ,
B.word AS NxtName
FROM words AS A
LEFT JOIN words AS B ON A.Id = B.Id - 1
LEFT JOIN words AS C ON A.Id = C.Id + 1
WHERE A.Word = 'name'
Result:
Fiddler Demo

Answer 5

Try this
SELECT *
FROM tablename a
WHERE ID IN(SELECT ID - 1
FROM tablename
WHERE word = 'name') -- will fetch previous rows of word `name`
OR ID IN(SELECT ID + 1
FROM tablename
WHERE word = 'name') -- will fetch next rows of word `name`
OR word = 'name' -- to fetch the rows where word = `name`

Answer 6

Here's a different approach, if you want the selects to be fast. It takes a bit of preparation work.
Create a new column (e.g. "phrase") in the database that will contain the words
you want. (i.e. the previous, the current and next).
Write a trigger that on insert appends the new word to the previous
row's phrase and prepends the previous row's word to the new row's word and fills
phrase.
If the individual words can change, you'll need a trigger on update to keep the phrase in sync.
Then just select the phrase. You get much better speed, but at the cost of extra storage and slower insert and harder maintainability. Obviously you have to update the phrase column for the existing records, but you have the SQL to do that in the other answers.