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copied!<p>If I understand you correctly, you want to be able to create a query that could have criteria based on any number of fields, which are unknown upfront. That's tough....</p> <p>While most RDBMS do offer some kind of "dynamic SQL" capability, those approachs tend to be either cumbersome to use, or slow, or both. </p> <p>Of course, you could also concatenate together a SQL statement in your client code, be it C#, Java, PHP or whatever - but that again will tend to be cumbersome, prone to SQL injection attacks, and in general rather clumsy.</p> <p>Also, if you have queries that are different from one request to another, the RDBMS won't be able to cache any of your query plans, and getting indexing right to get a decent query performance will be challenging at best, impossible at worst.</p> <p>So while I totally understand the requirement (and have to fight it off myself almost daily), it's really something that doesn't work well. I would rather try to identify the most frequently used searches and their criteria and make sure those work fine and are fast. Limit the user's flexibility in order to achieve a decent query performance. A classic trade-off - you can be totally flexible but then you have horrible performance, or you can make your frequent queries run fast - but loose some flexibility.</p> <p>One area where you could possibly gain something is when searching free text in text fields - RDBMS like SQL Server support the concept of a fulltext search, which gives you some flexibility and good performance. Check into that if you have lots of text fields.</p> <p>Marc</p>

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