SQL query to match entire sentence against keywords - sql

Question

I am trying to implement faq section on the website, where after will ask a question, the whole sentence will be matched again list of keywords and if any matched will be found, this will be returned back to user.
The database is running on MS SQL 2014,
+----+----------------------------------+----------------------------------------------------------+
| ID | Keywords | Answer |
+----+----------------------------------+----------------------------------------------------------+
| 1 | opening, open, hour, hours, time | We are open from 9AM to 6PM every day, Monday to Sunday. |
+----+----------------------------------+----------------------------------------------------------+
In this case, let's assume user will ask following question:
What time are you open?
This will be matched against the Keywords, as the 'time' is used in question and is among keywords, the first answer will be returned.
I would prefer to avoid using like for every single word in sentence if possible.
I tried using contains, but this doesn't work well with whole sentence:
SELECT * FROM FAQ
WHERE CONTAINS(Keywords,'"What time are you open?"');
http://sqlfiddle.com/#!6/895e5/1
Any help would be appreciated.

Answer 1

I suggest normalize your table and try this one
--create temporary table and populate data
Declare #keywordTable as TAble (ID INT, Keyword varchar(100))
declare #AnswerTable as table (ID int, Answer nvarchar(max))
declare #question nvarchar(max) = 'What time are you open?'
SET #question = REPLACE(#question,'?','')
INSERT #keywordTable
values
(1,'opening'),
(1,'open'),
(1,'hours'),
(1,'hour'),
(1,'time'),
(2,'keyword2'),
(2,'second')
insert #AnswerTable
values (1, 'We are open from 9AM to 6PM every day, Monday to Sunday.'),
(2, 'second question')
display data table
SELECT * FROM #keywordTable
ID Keyword 1 opening 1 open 1 hours 1 hour
1 time 2 keyword2 2 second
SELECT * FROM #AnswerTable
ID Answer 1 We are open from 9AM to 6PM every day, Monday to
Sunday. 2 second question
use function to split the question by words
ALTER FUNCTION [MDM].[fn_SplitString]
(
#string NVARCHAR(MAX),
#delimiter CHAR(1)
)
RETURNS #output TABLE(splitdata NVARCHAR(MAX)
)
BEGIN
DECLARE #start INT, #end INT
SELECT #start = 1, #end = CHARINDEX(#delimiter, #string)
WHILE #start < LEN(#string) + 1 BEGIN
IF #end = 0
SET #end = LEN(#string) + 1
INSERT INTO #output (splitdata)
VALUES(SUBSTRING(#string, #start, #end - #start))
SET #start = #end + 1
SET #end = CHARINDEX(#delimiter, #string, #start)
END
RETURN
END
This is the result of split function
SELECT * FROM [MDM].[fn_SplitString](#question,' ')
splitdata What time are you open
Final Query
SELECT Answer from #AnswerTable where ID in (select ID FROM #keywordTable where keyword in (SELECT * FROM [MDM].[fn_SplitString](#question,' ')))
Final Result
Answer We are open from 9AM to 6PM every day, Monday to Sunday.

Answer 2

Well one way could be break down the comma separated keyword into different rows and match them with the sentence.
And you can use any standard splitter. See this link here. I've used XML based because most likely your input should not contain any valid character.
I've also added multiple matching to SQL. This way if more than one answer has same keyword, the code will pick up the one with most keywords.
See working demo
declare #question varchar(max)
set #question='What time are you open?'
create table t ( ID int,Keywords varchar(max), Answer varchar(max));
insert into t
values
( 1,'opening, open, hour, hours, time','We are open from 9AM to 6PM every day, Monday to Sunday.'),
(2,'open,weekends', 'No we don''t!')
SELECT TOP 1
Max(Answer) as Answer
FROM t outer apply (
SELECT Item = y.i.value('(./text())[1]', 'nvarchar(4000)')
FROM
(
SELECT x = CONVERT(XML, '<i>'
+ REPLACE(Keywords, ',', '</i><i>')
+ '</i>').query('.')
) AS a CROSS APPLY x.nodes('i') AS y(i)
)T1
WHERE #question like '%'+Item+'%'
group by Id
order by count(1) desc