How to build search engine for website using sql server - sql-server

Question

I need some help with creating a simple search engine for website. Basic idea is that user will enter a string in search bar, which will compare in database key_word and get the results.
Let's say I have the following table in the SQL Server database:
|----|----------|----------------------|
| ID | URL | key_word |
|----|----------|----------------------|
| 1 | url1.com | cat short red NYC |
| 2 | url2.com | tall blue LA |
| 3 | url3.com | skinny NYC green |
| 4 | url4.com | cat black get |
|----|----------|----------------------|
Now in search bar, lets say user want to search the below string "get red cat from NYC". I want to search this in database 'key_word'.
String key = "get red cat from NYC"
What I have tried:
So far I have the following below query to search from database. This is good for if user want to search for only one word. but the string 'key' will not work here and it will return 0 result. I need some idea so I can make this better query.
SELECT *
FROM [SearchTable]
WHERE [key_Word] LIKE % key %;
What I want:
I want to change this sql server query so that it return ID=1,3,4.
So in other words. I want to take this string:
String key = "get red cat from NYC"
and first search in database the word "get". it doesn't show up so go to next word. Next word is "red", this shows up in ID=1. next word is "cat", this shows up in ID=1,4. Next word is "from", this doesn't show up in any rows. Next word is "NYC", this shows up in ID=1,3.
put all id's together and you get ID's=1,1,4,1,3.
than I want to sort it so that ID=1 shows up at top and ID=3,4 can be at button since they are tied.
I was hoping to do this by only one SQL query, because if I keep connecting to database than the speed will go down too. So I was think of some SQL Server functions?

Answer 1

You need a string splitter for this. See this article for some functions:
DECLARE #key VARCHAR(MAX) = 'get red cat from NYC'
SELECT t.ID
FROM tbl t
CROSS APPLY dbo.SplitStrings_XML(t.key_word, ' ') tx
INNER JOIN (
SELECT Item
FROM dbo.SplitStrings_XML(#key, ' ')
)k
ON k.Item = tx.Item
GROUP BY T.ID
ORDER BY COUNT(*) DESC
SQL Fiddle
Here is the SplitStrings_XML function:
CREATE FUNCTION dbo.SplitStrings_XML
(
#List NVARCHAR(MAX),
#Delimiter NVARCHAR(255)
)
RETURNS TABLE
WITH SCHEMABINDING
AS
RETURN
(
SELECT Item = y.i.value('(./text())[1]', 'nvarchar(4000)')
FROM
(
SELECT x = CONVERT(XML, '<i>'
+ REPLACE(#List, #Delimiter, '</i><i>')
+ '</i>').query('.')
) AS a CROSS APPLY x.nodes('i') AS y(i)
);
The above function will not work if your string has illegal XML characters like >, <, and &. You can use other splitter but the idea stays the same.