Question

I’m going to search my database (SQL Server 2008) using a stored procedure. My users can enter keyword(s) in a textbox (keywords can be separated using , for instance).

Currently I’m using something like this:

keyword like N"%'+@SearchQuery%'%"

(keyword is a nvarchar column in my table, and @SearchQuery is the input to my stored procedure)

It works fine but what if user types several keywords: apple,orange, banana

Should I limit number of my keywords? How should I write my stored procedure if I have more than one keyword? How should I pass my user input to the stored procedure? I should pass apple, orange, banana as a whole phrase and then I should parse them in my stored procedure, or I should separate my keywords and send 3 keywords? How can I query these 3 keywords? A for loop?

What are best practices for performing such queries?

thanks

Answer 1

You could use CTE to split the string of keywords in a temporary table and then use it as you like. The keyword list can even have numbers or any characters, like %$<> or what you want, just remember comma is the string separator

DECLARE @CommaSeparatorString VARCHAR(MAX),
        @CommaSeparatorXML XML
DECLARE @handle INT
SELECT @CommaSeparatorString = 'apple,orange,banana'
SELECT @CommaSeparatorString = REPLACE(REPLACE(@CommaSeparatorString,'<','$^%'),'>','%^$')
SELECT @CommaSeparatorXML   =   CAST('<ROOT><i>' + REPLACE(@CommaSeparatorString, ',', '</i><i>') + '</i></ROOT>' AS XML) 

SELECT REPLACE(REPLACE(c.value('.', 'VARCHAR(100)'),'$^%','<'),'%^$','>') AS ID
  FROM (SELECT @CommaSeparatorXML AS CommaXML) a
 CROSS APPLY CommaXML.nodes('//i') x(c)

Result:

  ID
------
apple
orange
banana