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Tag: sql

Delete cascade Category child (Java Hibernate JPA)

I have this Entity to represent a Category system with a selfrelationship to get child categories: The problem is when I want to delete a category that has child categories. I want to delete all child categories but Java drops me this exception : Cannot delete or update a parent row: a foreign key constraint …

Joining table only once in SQL

I’m sure this is very basic, but I’ve hit a brick wall. First post here, long time reader. I’ve got two tables, one is a list of customers, one is a list of their activity by month. For some unknown reason, some of the data in the activity column is duplicated and it’s causing me error…

PL SQL Pivot: use different aggregates

I want to pivot sum(sales) per country as below. But the price column should be an average per shop. So, I would love to have this result: Desired Result: shop avg_price US CN 2 6 100 10 3 5 60 10 Current Result: shop price US CN 2 5 null 5 2 7 100 5 3 5 60 10 I

Postgresql SELECT sample with FOR loop

I have a task where I need to create a 1000 sample row limit query for each attribute selected. So for example if I have: I would need to turn this in to: Problem is that I have a lot of these attributes and that I might be adding more attributes later. Is there a better way of writing this?

How to prevent unintended default values from MyBatis queries?

I have the following Java class: The class represents a database table called example. I can use the following SQL query to fetch Example instances from the table with MyBatis: Let’s say that I will add a new field to the table and the class: boolean third. However, if I don’t remember to add the …

Group by month and name SQL

I need some help with SQL. I have Table1 with columns Id, Date1 and Date2 Table2 with columns Table1Id and Table2Id Table3 with columns Id and Name Here is my try: I need to take Count(date2)/Count(date1) grouped by monthes and name. I have no idea how to do that, as there is no table with monthes. DB –…

Oracle SQL: How to fetch only style tag attributes from column?

I want to fetch only style tag attributes from a column i.e., style tag between double quotes (“). Style= can be anywhere in the column. Below is the sample data: Expected: Output: Tried below code: With this I am getting double quotes also in the output. Need help on how to get only style tags without …

How to select and view database with specific value?

So I’m trying to search and print the value from the PHPMyAdmin database. But the result shows all row which has variable with containing the value. Like when I try search variable int bulan that has value 2. This also shows a row that has a value of 12, 22 or 23 as a result. this is my code Answer