Category: T-SQL

Shane O’Neill tries something out:

Now, SQL Server doesn’t have the filter option, but we can do some pretty weird things, like a SELECT...WHERE statement with no FROM clause.

SELECT

    a,b,c,

    [filter?] = (SELECTb WHEREb > 11)

FROMz;

GO

It turns out that this works, but when you try to aggregate the results, it doesn’t work the way Shane expected. Using the APPLY operator does help here, so click through to see how that works.

Louis Davidson chooses the form of our destroyer:

I preface a lot of what I write with whether or not it is for a “practical” use. One of the Simple Talk authors used this function in a forthcoming article. and I realized I hadn’t heard of it before (or I forgot about it… which is not completely unlikely.) The practical use was to generate some data and have at least a little variety to the values.

The CHOOSE function has this syntax.

CHOOSE(item_to_choose, item1, item2 [,item3]…[itemN])

In fairness to Louis, CHOOSE() was one of those additions to SQL Server 2012 that we mostly forgot about. It’s similar in that vein to IIF() if you weren’t living in Excel at the time. In any event, Louis takes CHOOSE() through its paces, showing some useful scenarios and stretching the limits to see what happens.

Andy Brownsword takes a look at one quality of life improvement in SQL Server 2022:

Window functions allow us to perform a function across a set of rows in a result set, rather than how we might typically group them. In SQL Server 2022 we have a new clause available for our queries which can help tidy up how these are defined.

You can do some neat things with the WINDOW clause, including partial matches. For example, you could define a window r1 AS (PARTITION BY x.MyColumn) and then another window r2 AS (r1 ORDER BY x.SomeOtherColumn). I don’t think there are a huge number of scenarios in which this is helpful, especially because performance typically depends upon minimizing the unique number of window functions in your query, but every once in a while it’s a really neat thing.

Vlad Drumea is looking for matches:

Figuring out object dependencies in a SQL Server database, especially one you’re not familiar with, can be a challenge.
Luckily, Microsoft provides the sys.sql_expression_dependencies system catalog view to help DBAs and developers track down various object dependencies.

I leveraged this catalog view in a query that returns the necessary info in a more user-friendly way, while also allowing easy filtering for referenced or referencing object.

Click through for the script. It’s been a while since I’ve used this DMV in anger, though my recollection is that I had problems finding dependencies over linked servers.

Rajendra Gupta shows off a nice feature in SQL Server 2022:

Suppose you are a data strategist or analyst for an organization. You have been tasked with getting actionable insights from customers who want to track customer patterns at different intervals, such as hourly, daily, or weekly. To do this, you need to use several date functions such as DATEADD, DATEDIFF, DATEPART, and DATEFROMPARTS to get the required date format.

In SQL Server 2022, this got a lot easier to do using the DATETRUNC function.

Solutions using DATETRUNC() are significantly easier to read and understand than the alternative of combiningDATEADD() and DATEDIFF()