See here for font conventions used in this article. Introduction It is very common in information systems to have functions where the users are able to search the best 15 minute binary option strategy by selecting freely among many possible criterias.
When it comes to the latter, there is a key theme: there is no single execution plan that is good for all possible search criterias. Rather, you want the query plan to be different depending on user input. There are two ways to achieve this. Or you can use dynamic SQL to build a query string which includes only the search criterias the user specified. We will look at both these approaches in this article. They are both viable, and a good SQL programmer should have both in his toolbox since both have their strengths and weaknesses.
This article assumes that you are on SQL 2008 or later. SQL 2005, but which was implemented properly first in SQL 2008. And to be precise, you should be on at least Service Pack 2 of SQL 2008, or Service Pack 1 for SQL 2008 R2 to take benefit of this feature. I begin the article looking at some methods which are good for very simple cases where you only need to handle a very small set of choices and where the more general methods shoot over the target.
The two main chapters of this article look at implementing this procedure with static and dynamic SQL. Alternate Key Lookup Using IF statements Problems with dynamic search conditions come in several flavours. In the general case, there is a search form where the user can select between many search conditions, and this is also the main focus of this article. But sometimes you encounter problems with a small number of conditions that are more or less mutually exclusive.