Flyspeed Sql Query Serial Number ((HOT))
note that row_number() is a newly-introduced feature in sql 2005. if you are using any previous version, you will have to use the subquery approach (you can also use a self-join, to write it a bit differently). using the recently introduced pivot operator, you can write this as follows:
Flyspeed Sql Query Serial Number
when the number of rows is small and almost known beforehand, it is easier to generate the code. one common approach where there is a small set of finite rows is the pivoting method. here is an example where only the first four alphabetically-sorted product names per categoryid is retrieved:
if you know that the table contains no more than 10 rows per product, it is more efficient to generate the code with a subquery. this time, the result set is already filtered. the union operator can be used to combine multiple result sets.
before the release of dbforge query builder, i have faced the dilemma of which approach to use. either i'd have to learn tsql or write a query using the new features in sql server 2005. many times, i have taken the latter route. i tried to write a set of templates and then call them. i also tried to modify the sql code to make it a bit more generic. but when i had to do more work or wanted to reuse the code, the sql code turned out to be cumbersome and lacking the necessary domain support.
with the introduction of the ctes, i have decided to move away from the code-based approach and go for the template approach. i have used the cte template approach in dbforge query builder to create a set of snippets which can be used to generate the desired resultsets.