SQL and Scikit Learn

Aggregate functions

Functions that perform a calculation on a set of values and return a single value, like AVG, SUM, MIN, MAX, COUNT.

AVG

An aggregate function that calculates the average of a numeric column.

SUM

An aggregate function that returns the total sum of a numeric column.

MIN

An aggregate function that returns the smallest value in a set.

MAX

An aggregate function that returns the largest value in a set.

COUNT

An aggregate function that returns the number of rows that match a specified criterion.

ROUND function

Used to round a number to a specified number of decimal places.

Negative number with round

Rounding can affect negative numbers similarly to positive numbers, depending on the rule used.

Rounding to nearest thousandth

Rounding a number to three decimal places.

Arithmetic with SQL queries

SQL can perform arithmetic operations within SELECT statements.

Aliasing

Assigning a temporary name to a column or result set for easier referencing.

SELECT (gross - budget) AS profit

An SQL expression that creates an alias 'profit' for the result of 'gross - budget'.

Order of execution in SQL

The sequence in which SQL processes queries: FROM → WHERE → SELECT → LIMIT.

Integer division in SQL

When dividing two integers, SQL will return an integer result, discarding any decimal.

Supervised Learning

A type of machine learning where the model is trained on labeled data.

Feature

An individual measurable property or characteristic used for analysis in supervised learning.

Target

The output variable that the algorithm aims to predict during supervised learning.

Data Wrangling

The process of cleaning and transforming raw data into a usable format.

EDA (Exploratory Data Analysis)

Analyzing data sets to summarize their main characteristics, often using visual methods.

Feature Engineering

The process of using domain knowledge to extract features that make machine learning algorithms work.

Feature Matrix

A two-dimensional array where rows represent samples and columns represent features.

Target Vector

The vector representing the outcomes you want to predict, used in supervised learning.