to loop or not to loop?

[jodunno]

20 minutes ago, Barand said:

I fell foul of that this morning. It worked fine yesterday when I posted the query but when I loaded some more data and ran it again after midnight I got nothing. The last date I had was 2025-01-26 so -7 DAY worked fine on the 2nd Feb but not on the 3rd.

On the subject of temporary tables, have a look at WITH RECURSIVE. There may be occasions when you want to list, say, total sales for each day last month and show a zero total for days with no sales. You can't just sum, grouping by the dates, as you won't get output if there is no data fora  date. You need a table containing all the dates in the month and use a left join. WITH RECURSIVE gives a great way of create such a temporary date table on the fly.

easy to forget, i guess. I'm used to working on my own projects on an up-to-date xampp installation. I just forgot that we have an outdated dump file. I suppose that it is simply a common mistake when focusing on the code.

I have found several resources on the recursive cte topic:

https://dev.mysql.com/doc/refman/8.4/en/with.html
https://www.mysqltutorial.org/mysql-basics/mysql-recursive-cte/
https://bobcares.com/blog/mysql-recursive-cte/
https://mariadb.com/kb/en/with/
https://mariadb.com/kb/en/recursive-common-table-expressions-overview/
https://matthewdaly.co.uk/blog/2022/12/18/two-techniques-for-handling-recursive-relationships-in-mysql/
 

I'm going to play with this concept to gain some experience as quickly as possible, although mastering the subject will cost some time. Very fascinating. I need to upgrade my knowledge of sql in the process of this forum.

Thanks for the tip, Barry. Now please spend some time relaxing. I have to log off now as my son has an appointment with a doctor. I will be back in a few hours, then i will continue upgrading my sql skills.