Using group by on multiple columns

Group By X means put all those with the same value for X in the one group. Group By X, Y means put all those with the same values for both X and Y in the one group. To illustrate using an example, let’s say we have the following table, to do with who is attending what subject at … Read more

Must declare the scalar variable

You can’t concatenate an int to a string. Instead of: You need: To help illustrate what’s happening here. Let’s say @RowTo = 5. In order to build that into a string (even if ultimately it will be a number), I need to convert it. But as you can see, the number is still treated as … Read more

ORA-00907: missing right parenthesis

I have been looking at this code for the past two days now and I can not seem to get it to work. It keeps giving me ORA-00907: missing right parenthesis. I know that this is a topic that comes up a lot but for some reason none of the examples I have seen has … Read more

ORA-00979 not a group by expression

You must put all columns of the SELECT in the GROUP BY or use functions on them which compress the results to a single value (like MIN, MAX or SUM). A simple example to understand why this happens: Imagine you have a database like this: and you run SELECT * FROM table GROUP BY foo. … Read more

How do I use MySQL through XAMPP?

XAMPP only offers MySQL (Database Server) & Apache (Webserver) in one setup and you can manage them with the xampp starter. After the successful installation navigate to your xampp folder and execute the xampp-control.exe Press the start Button at the mysql row. Now you’ve successfully started mysql. Now there are 2 different ways to administrate … Read more

Must declare the scalar variable

You can’t concatenate an int to a string. Instead of: You need: To help illustrate what’s happening here. Let’s say @RowTo = 5. In order to build that into a string (even if ultimately it will be a number), I need to convert it. But as you can see, the number is still treated as … Read more