Updating a row in sql server 2016
Concatenating column values or expressions from multiple rows are usually best done in a client side application language, since the string manipulation capabilities of Transact SQL and SQL based DBMSs are somewhat limited.
However, you can do these using different approaches in Transact SQL, but it is best to avoid such methods in long-term solutions Even though SQL, in general, deviates considerably from the relational model, its reliance on certain core aspects of relational foundations makes SQL functional and powerful.
Using common table expressions and the ROW_NUMBER() function, you can re-write this as: Note that ROW_NUMBER() is a newly-introduced feature in SQL 2005.
(Talking about 1NF violations in a language like SQL which lacks sufficient domain support, allows NULLs and supports duplicates is somewhat ironic to begin with, but that is a topic which requires detailed explanations.) By ‘Concatenating row values’ we mean this: You have a table, view or result that looks like this……and you wish to have a resultset like the one below: In this example we are accessing the sample North Wind database and using the following SQL The objective is to return a resultset with two columns, one with the Category Identifier, and the other with a concatenated list of all the Product Names separated by a delimiting character: such as a comma.There is no grouping or logical partitioning of values such as the list of email addresses separated by a semicolon or some such.In such situations, the approaches can be the same except that the join conditions may vary.So approaches that are loosely called “concatenating row values”, “aggregate concatenation” etc.would have to make sure that some kind of an order, either explicit or implicit, should be specified prior to concatenating the row values.For instance, the recursive common table expressions (CTEs) and the FOR XML PATH(”) syntax makes the server do the hard work behind the concatenation, leaving the programmer to deal with the presentation issues. The idea behind this method is from a newsgroup posting by Vadim Tropashko.It is similar to the ideas behind generating a materialized path for hierarchies.Northwind is a sample database in SQL Server 2000 default installations.You can download a copy from from the Microsoft Downloads When the number of rows is small and almost known beforehand, it is easier to generate the code.It may be better to look at each of them separately.In some cases, all the programmer wants is just the list of values from a set of rows.