SQL Reference

Basic Queries

Select one or more columns of data from a table:

SELECT column_name_1, column_name_2 FROM table_name;

Select all of the columns in a table:

SELECT * FROM table_name;

Get only unique lines in a query:

SELECT DISTINCT column_name FROM table_name;

Perform calculations in a query:

SELECT column_name_1, ROUND(column_name_2 / 1000.0) FROM table_name;


Select only the data meeting certain criteria:

SELECT * FROM table_name WHERE column_name = 'Hello World';

Combine conditions:

SELECT * FROM table_name WHERE (column_name_1 >= 1000) AND (column_name_2 = 'A' OR column_name_2 = 'B');


Sort results using ASC for ascending order or DESC for descending order:

SELECT * FROM table_name ORDER BY column_name_1 ASC, column_name_2 DESC;


Combine data into groups and calculate combined values in groups:

SELECT column_name_1, SUM(column_name_2), COUNT(*) FROM table_name GROUP BY column_name_1;


Join data from two tables:

SELECT * FROM table_name_1 JOIN table_name_2 ON table_name_1.column_name = table_name_2.column_name;

Combining commands

SQL commands can be combined in the following order: SELECT, FROM, JOIN, ON, WHERE, GROUP BY, ORDER BY.