SQL

Functions

Comments:

SELECT name; # Comment
SELECT name, /* inline comment */, population
/*
Multiple lines
comment
*/

# XOR : exclusive OR == one condition or the other but not both
SELECT name, population, area
FROM world
WHERE area > 3000000
XOR population > 250000000

ORDER BY column_name ASC, other_column DESC

Functions

ROUND(number/1.5, 2) // Round the result of an operation to two decimals

# CASE
# Conditionally alter values
SELECT name,
       CASE WHEN continent='Oceania' THEN 'Australasia'
            ELSE continent
            END
FROM world
WHERE name LIKE 'N%'