SQL Commands and Operators Quiz

Study Notes

SQL Commands and Operators

SQL commands are terminated by a semicolon (;).
SELECT * FROM VACATION_PACKAGES; displays all data in the VACATION_PACKAGES table.
Primary keys cannot be NULL.
SELECT * FROM table_name; displays all rows and columns from a table.
* (asterisk) represents all columns in a SELECT statement.
IS NULL represents empty or unknown values in SQL.
SELECT is the fundamental command for querying databases.
ORDER BY clause sorts data within rows.
You can use both WHERE and HAVING clauses (if involving groups). WHERE filters before grouping, HAVING filters groups.
GROUP BY groups rows with similar values, not sorts them.
ORDER BY UNIT_PRICE sorts results in ascending UNIT_PRICE order.
Nested queries (queries within a query) are possible.
SELECT statements do not always require a WHERE clause.
IS NOT NULL finds rows where a specific column is not NULL.
IN operator selects rows matching specific values in a list (e.g., "Red", "Pink", "White").
BETWEEN operator selects values within a specified range (inclusive).
COUNT determines the number of rows in a table.
SUM calculates the total of values in a column.
The base SELECT structure involves SELECT, FROM, and potentially WHERE.
Various arithmetic operators (+, -, *, /, etc.) can refine SELECT statements.

Wildcards and Pattern Matching

LIKE operator uses wildcards for pattern matching (e.g., %).
% is a wildcard representing any character sequence (zero or more characters).

NULL Values

IS NULL finds rows containing null values in a specified column.

Description

Test your knowledge on SQL commands and operators with this quiz! Learn how to effectively use SELECT, INSERT, UPDATE, and more to manipulate your data. Understand the nuances of clauses like WHERE, HAVING, and ORDER BY to enhance your database queries.