How do I use properly CASE..WHEN in MySQL
Remove the course_enrollment_settings.base_price immediately after CASE: CASE has two different forms, as detailed in the manual. Here, you want the second form since you’re using search conditions.
SQL
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
How can I do an UPDATE statement with JOIN in SQL Server?
Syntax strictly depends on which SQL DBMS you’re using. Here are some ways to do it in ANSI/ISO (aka should work on any SQL DBMS), MySQL, SQL Server, and Oracle. Be advised that my suggested ANSI/ISO method will typically be much slower than the other two methods, but if you’re using a SQL DBMS other … Read more
Online SQL Query Syntax Checker
SQLFiddle will let you test out your queries, while it doesn’t explicitly correct syntax etc. per se it does let you play around with the script and will definitely let you know if things are working or not.
NOT IN vs NOT EXISTS
I always default to NOT EXISTS. The execution plans may be the same at the moment but if either column is altered in the future to allow NULLs the NOT IN version will need to do more work (even if no NULLs are actually present in the data) and the semantics of NOT IN if NULLs are present are unlikely to be the ones you … Read more
SQL SELECT WHERE field contains words
Rather slow, but working method to include any of words: If you need all words to be present, use this: If you want something faster, you need to look into full text search, and this is very specific for each database type.
How to create Temp table with SELECT * INTO tempTable FROM CTE Query
Sample DDL Make sure that the table is deleted after use