FREE POINTS
SELECT AVG(SUM(salary))
FROM employees
GROUP BY department_id;
SELECT AVG(dept_total) AS avg_dept_salary
FROM (
SELECT SUM(salary) AS dept_total
FROM employees
GROUP BY department_id
) AS dept_sums;
It is the SQL clause used to arrange rows that share the same values into groups.
What is GROUP BY?
It is the language subset of SQL used to define and modify database structures.
What is DDL (Data Definition Language)?
It is bad practice to skip defining these constraints, which ensure that related data across tables stays consistent.
What are foreign keys?
(noun) a definite or clear expression of something in speech or writing.
STEAM TENT
What is STATEMENT?
This function returns the aggregated total of the non-null numeric expression values in a group.
What is SUM()?
It is data that has been summarized or combined using functions like COUNT, SUM, or AVG.
What is aggregated data?
It is the rule that ensures every row in a table can be uniquely identified.
What is a primary key?
It is risky to perform DELETE or UPDATE operations without this clause.
What is WHERE?
(noun) A question posed to gain clearer information within a context.
BUY QUERS
What is SUBQUERY?
This function calculates the average value of a numeric column or expression in a group.
What is AVG()?
What is AVG()?
The column or expression specified in the GROUP BY clause is the component that rows are grouped by.
What is a grouping attribute?
Is a broad concept of ensuring the accuracy and consistency of data
What is Data Integrity?
Not adding these to tables with frequently accessed data can cause bottlenecks and performance issues.
Hint: These can be (but are not limited to) unique or composite.
What is an Index?
(noun) a structured set of data held in a computer, especially one that is accessible in various ways
A Bad Seat
What is DATABASE?
THESE functions return the maximum (largest) and minimum (smallest) expr value in a group.
What are MAX() and MIN()?
It is raised if a GROUP BY clause is present, but that item is not a grouping attribute·
What is an error?
(DING DING DING! Let's go gambling.) It is the database principle summarized by the acronym ACID.
What are Atomicity, Consistency, Isolation, and Durability?
Failing to do this with your JDBC connections can cause memory leaks and exhaust your connection pool.
What is not closing database connections?
(noun) A person regarded as having an innate gift or talent for a particular task or activity.
At lunar
This function calculates the average value of a numeric column or expression in a group.
What is AVG()?
Group functions are allowed in the ORDER BY clause, but not in this clause.
What is WHERE?
It is the SQL concept that allows multiple users to safely access and modify the same data at once.
What is a transaction?
You leave yourself vulnerable to this type of hacking if you concatenate user input directly into SQL statements without validation.
Hint: It is one of the most common hacking attacks.
What is SQL injection risk?
(adj) relating to a French Philosopher and his ideas.
Ara nicest
What is Cartesian?