Question

First I apologize for the poor formatting here.

Second I should say up front that changing the table schema is not an option.

So I have a table defined as follows:

Pin varchar
OfferCode varchar

Pin will contain data such as:
abc,
abc123

OfferCode will contain data such as:
123
123~124~125

I need a query to check for a count of a Pin/OfferCode combination and when I say OfferCode, I mean an individual item delimited by the tilde.

For example if there is one row that looks like abc, 123 and another that looks like abc,123~124, and I search for a count of Pin=abc,OfferCode=123 I wand to get a count = 2.

Obviously I can do a similar query to this:
SELECT count(1) from MyTable (nolock) where OfferCode like '%' + @OfferCode + '%' and Pin = @Pin

using like here is very expensive and I’m hoping there may be a more efficient way.

I’m also looking into using a split string solution. I have a Table-valued function SplitString(string,delim) that will return table OutParam, but I’m not quite sure how to apply this to a table column vs a string. Would this even be worth wile pursuing? It seems like it would be much more expensive, but I’m unable to get a working solution to compare to the like solution.

Answer 1

Your like/% solution is open to a bug if you had offer codes other than 3 digits (if there was offer code 123 and 1234, searching for like ‘%123%’ would return both, which is wrong). You can use your string function this way:

SELECT Pin, count(1) 
FROM MyTable (nolock) 
CROSS APPLY SplitString(OfferCode,'~') OutParam 
WHERE OutParam.Value = @OfferCode and Pin = @Pin
GROUP BY Pin

If you have a relatively small table you can probably get away with this. If you are working with a large number of rows or encountering performance problems, it would be more effective to normalize it as RedFilter suggested.