Category: SQL Server

The GROUP BY clause in SQL is used to get only unique rows. You have to specify only the columns you want them evaluated by – and the same ones both after GROUP BY and after SELECT. The only exception is aggregate functions (SUM,AVG, etc.). That is not a problem at all, though, because (with …

I just had a bit of a small shock, but it is my own fault for clicking through things I do not understand without looking into them first. I am still building several pages for statistics, archiving, sharing and so on of GPX files from Garmin navigation devices, and surely from others too (it is …

At first I tried it with a column of type Real, so the column definition was, for example, Column(1,1), but that always gave me an error “Parameter or variable ‘Column’ has an invalid data type.”. So I tried it with the Decimal data type instead. In general, let’s take the column definition Column(2,1) as an …

I looked this up once before, but since I never ended up using it and didn’t really need it again, I forgot how it works and everything else about it. Today this picture, which I found on stackoverflow, helped me a lot to get the basic idea: Then I created these 2 tables in SQL …

I have now applied this fix on my website sunamo.cz/sunamo.net. I had run into this error before when opening several pages in a row, but I did not know what it meant, since I do not use the SqlDataReader or DataReader class anywhere in the application. Then today I tried to open all 7 of …

I am writing this guide mainly for myself, in case I ever need to reinstall Windows 8, so it may not match your needs exactly. I am working with W8 here (not W8.1) because my PC comes with an installation disc for W8. However, the upgrade to W8.1 is free for everyone, so I tried …

It’s really simple. I went through a lot of pages that mostly advised changing the account the SQL Server service runs under to your own account, but I didn’t want to do that. After all, if it were meant to be that way, MS would have set it up like that, and it wouldn’t run …

The full text of this error reads: Unable to open physical file … Operating system error 5: “5(error not found)” (Microsoft SQL Server: Error 5120), where the … will be replaced by the full path to the database you are trying to attach. I am not sure I will describe everything here perfectly down to …

You may not believe it, but I have usually had some kind of problem with SQL Server. It always cost me at least an hour of googling, and sometimes I even had to give something up just to end up with something less than perfect. The last time this happened was less than a week …

Testing methodology: 2 databases were created, each with a single table containing only an int column and an NVarChar(20) column. The first one always received NULL values in the NVarChar column, while the second database received empty strings. Once again, my goal here is to save as much space as possible. And the result? The …