The SELECT command is used to search database tables for specific records.

There is always a SELECT and a FROM, but there may or not be a WHERE or ORDER BY

The order is of these lines must be:

SELECT columns
FROM tables
WHERE conditions
ORDER BY sorting

SELECT & FROM lines

Specify which fields are to be displayed, and which tables are to be used

Display all columns

SELECT *
FROM orders 

Display some columns

SELECT product, customer, quantity
FROM orders

WHERE conditions (optional)

This is used to select records from the tables. Conditions are described on the Conditions reference page.

If there is no WHERE line, then all records are displayed

SELECT product, customer, quantity
FROM orders
WHERE quantity > 100 

ORDER BY sorting (optional)

Specify the sorting order of columns

Single Column sort, ascending order

SELECT product, customer, quantity 
FROM orders 
ORDER BY quantity ASC

Single Column sort, descending order

SELECT product, customer, quantity 
FROM orders 
ORDER BY quantity DESC

Two Column sort

SELECT product, customer, quantity 
FROM orders 
ORDER BY quantity DESC, product ASC

Queries across two tables

When a column name appears in both tables, the name of the table must be included (eg customers.customer_id). (line 1)

The primary key and foreign keys of each pair of tables must be connected in the WHERE section (line 3)

 
SELECT forename, surname, customers.customer_id, product, quantity
FROM orders, customers
WHERE orders.customer_id = customers.customer_id