Efficiently convert rows to columns in sql server

There are several ways that you can transform data from multiple rows into columns. Using PIVOT In SQL Server you can use the PIVOT function to transform the data from rows to columns: See Demo. Pivot with unknown number of columnnames If you have an unknown number of columnnames that you want to transpose, then you can use dynamic SQL: See Demo. Using … Read more

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

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)