SELECT star in SQL

The star is fine at a prompt and a liability in code that has to keep working.

SELECT *
FROM products;

SELECT
    o.*,
    c.name
FROM orders AS o
JOIN customers AS c
    ON c.id = o.customer_id;

How it works

1. * expands to every column, in the table's declared order.
2. o.* takes every column from one table in a join.
3. Naming the columns you want survives an ALTER TABLE that adds one.

Keywords and builtins used here

• AS
• FROM
• JOIN
• ON
• SELECT
• c

The run, in numbers

Lines

9

Characters to type

105

Tokens

30

Three-star pace

70 tpm

At the three-star pace of 70 tokens a minute, this run takes about 26 seconds.

Type this snippet

Step 2 of 5 in Selecting rows, step 2 of 23 in Language basics.

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