Database Systems, unit: SQL Fundamentals. Core concepts, terminology, and worked-example cues a college student meets for this unit, building on prior units without repeating them. Front: a term, concept, or short problem cue. Back: the definition, explanation, or answer.
20 cards · basic cards · AI-written, checked twice. Edit anything.
- What is SQL?
- Structured Query Language, used to define, manipulate, and query relational databases
- What does the SELECT statement do?
- Retrieves data from one or more tables
- What does the WHERE clause do?
- Filters rows based on a specified condition
- What does the INSERT statement do?
- Adds new rows of data into a table
- What does the UPDATE statement do?
- Modifies existing data in a table
- What does the DELETE statement do?
- Removes rows from a table
- What does the CREATE TABLE statement do?
- Defines a new table and its columns
- What is a JOIN used for?
- Combining rows from two or more tables based on a related column
- What is an INNER JOIN?
- A join that returns only rows with matching values in both tables
- What is a LEFT JOIN?
- A join that returns all rows from the left table, with matches from the right table or nulls
- What does the GROUP BY clause do?
- Groups rows sharing a value into summary rows
- What does the ORDER BY clause do?
- Sorts the result set by one or more columns
- What is an aggregate function?
- A function that performs a calculation on multiple rows, such as COUNT, SUM, or AVG
- What does the HAVING clause do?
- Filters groups after aggregation, similar to WHERE for individual rows
- What is a subquery?
- A query nested inside another query
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