Tag: database

How do I check if a column have more than two items and if it have than do the avg() on it in SQL?

I have 4 tables The user and item from buys and rates are foreign keys. I can`t figure out how to put a condition to take out the items which have only one rating and do the average only on the ones who have 2 or more ratings. This is the question in the exercises (For each item that has

Oracle 10g sql query

database oracle sql

I have some data like this ↓ T_ID T_PERIOD T_COUNT T_SUM T_UPDATE_COUNT 1 2013-2014 3436 20118043 0 2 2014-2015 4298 27101356 0 3 2015-…

How does page overflow with columns (InnoDB) work in MySQL?

data-structures database mariadb mysql sql

The documentation says: “Whether columns are stored off-page depends on the page size and the total size of the row.” 1.- This means that if I have a page size of 16KB, the maximum size of the row would be 8KB, therefore, if I have 4 columns, will the maximum size of each column be 2KB (approximately)? 2.- When the

Django QuerySet annotate with Subquery

database django python sql

given the following model I’m trying to get, my Pizza and the number of toppings, along with the top 3 other pizzas (top in terms of the number of toppings) The final result should be: a list containing the current pizza, and the top 3 pizzas, along with the count of toppings for all. So right now I have a

Django complex partitioning & ordering for tree Table

database django postgresql python sql

I’m using Django with PostgreSQL as my Backend-Stack for an application of which the main feature is a complex, multilevel table displaying annotated time-series-data for different products. So …

Difference between JOIN and Inner JOIN in Sybase

database sql sybase

I have a query like below. I don’t understand the difference between join vs inner join used on the below code. Aren’t they the same? This is written for Sybase. Please help me know the difference. Answer According to the standard INNER JOIN=JOIN. I think, Sybase does not break this rule

how to convert this sql query to liquibase query

database liquibase sql

I have table like this I need to delete all duplicated rows with equals A nad B value and lower C value after running sql script i need to have only this row with top C Value for every equals A and B columns this is the sql query i am using how to convert it to liquibase query Answer

Linking two tables where the same value exists, without Primary key – SQLAlchemy

database python sql sqlalchemy

I have the following tables defined (very simplified version): I am using BigCommerce API and have multiple order_ids in both tables. The order_id is not unique globally but is unique per store. I am trying to work out how to link the two tables. I do have a Store table (shown below) that holds the store.id for each store, but

Relational Model – DBMS

database sql

I was going through some exercise problems to check my understanding of the relational model. According to my understanding, if we are given Album[mid] ⊆ Musician[mid], we can translate it into plain English as “Every album in the Database must have at least one musician”. If my understanding is right, How can the answer be “atmost” as given in the

SQLI Query not Updating NULL

database sql

I am having a problem with updating a NULL value in SQLI. There are no errors but it just stays at null. I am trying to get every NULL value in the optional_security_question and turn it into Not Available instead. Answer Try to use this syntax: