Author: Jay

They say the only three numbers in computer science are 0, 1, and N. Well, I’ll be at the SQL Saturday in Columbus, Ohio, on July 11th, giving a session entitled Playing in Traffic. It’s really a talk about keeping the wheels turning as a SQL developer when N gets really big. It’s the last session of the day, so expect things to be a bit laid back and mildly entertaining, but hopefully still very educational. See you in Columbus!

I’ll be presenting my session from SQL Saturday #358 at this month’s IndyPASS meeting next Tuesday, 3/17. I’m looking forward to all the heckling I’ll be getting from the Salesforce Marketing Cloud‘s performance DBA’s that will be in attendance.

Meeting attendees will also get an added bonus. I have a voucher for a free SQL Admin Toolset from Idera that will be part of the prize drawing. This was courtesy of Idera’s support of #358 in Albuquerque.

So, free pizza, the chance to heckle me, and the chance to win free software… what else could you ask for? See you Tuesday!

I was very happy with the response to my SQL Saturday session in Albuquerque. To those who attended and provided me with feedback, thank you.

One of the items I covered led to this tweet from @coffegrl:

Which just made my day yesterday. Anyway, here’s what she was talking about. Have a look at this script:


DECLARE @stmt NVARCHAR(MAX);
SELECT @stmt = N'foo' + REPLICATE(N'A', 4000) + N'bar';
SELECT LEN(@stmt), LEFT(@stmt, 5), RIGHT(@stmt, 5);


What happens when you run it? Ideally, the results should be 4006, ‘fooAA’ and ‘AAbar’. But that’s not the case. Even though @stmt is NVARCHAR(MAX), the four components of the string concatenation (‘foo’, ‘A’, the results of REPLICATE, and ‘bar’) are not. As a result, the value that is constructed is, in this case, an NVARCHAR(4000), which is then written to @stmt.

Here’s one way to fix it:


DECLARE @stmt NVARCHAR(MAX);
SELECT @stmt = N'foo' + REPLICATE(CAST(N'A' AS NVARCHAR(MAX)), 4000) + N'bar';
SELECT LEN(@stmt), LEFT(@stmt, 5), RIGHT(@stmt, 5);


And another:


DECLARE @stmt NVARCHAR(MAX);
SELECT @stmt = N'foo' + CAST(REPLICATE(N'A', 4000) AS NVARCHAR(MAX)) + N'bar';
SELECT LEN(@stmt), LEFT(@stmt, 5), RIGHT(@stmt, 5);


And another:


DECLARE @stmt NVARCHAR(MAX);
SELECT @stmt = CAST(N'foo' AS NVARCHAR(MAX)) + REPLICATE(N'A', 4000) + N'bar';
SELECT LEN(@stmt), LEFT(@stmt, 5), RIGHT(@stmt, 5);


And the same is true for VARCHAR (assuming you replace the 4000’s with 8000’s). So, the lesson is, when concatenating large strings in SQL be careful that it doesn’t trunca

I’m preparing for my session at SQL Saturday #358 in Albuquerque next week, and something finally clicked. I’ll be adding another demo to my section on the differences between EXEC and sp_executesql now. Want to find out what it is? Then come to Albuquerque!

Gotta love those A-ha moments!

I’m excited to announce that I’ll be presenting “Fast and Furious Dynamic SQL” at SQL Saturday #358 in Albuquerque on February 7th, 2015. This will be my first time as a PASS presenter, so please save your best heckling and rotten vegetables for the occasion.

The session will cover various tips and tricks that are generally related to running sp_executesql from within a stored procedure. It will focus on performance, security, and maintainability.