Select Computed Columns With Expressions

Include arithmetic, string, or conditional expressions directly in a `SELECT` list and give them an alias with `AS`.

Created Apr 26, 2026 Last updated Apr 26, 2026 5/5 supported engines validation-green 1 example 2 scenarios

Docker-validated Not currently validation-green

Example 1

Compute the total stock value for each inventory item

price * quantity is evaluated per row and named total_value with AS. The alias can then be used in ORDER BY to sort by the computed column. Cherries (5 × 30 = 150) rank first, then Apples (2 × 50 = 100), then Bananas (1 × 80 = 80).

Source table data Rows loaded before the example query runs.

Setup

CREATE TABLE inventory (id INT, name VARCHAR(50), price INT, quantity INT);

INSERT INTO
  inventory
VALUES
  (1, 'Apples', 2, 50),
  (2, 'Bananas', 1, 80),
  (3, 'Cherries', 5, 30);

Validated query Shared across supported engines.

SQL

SELECT
  name,
  price,
  quantity,
  price * quantity AS total_value
FROM
  inventory
ORDER BY
  total_value DESC;

Expected result Returned rows for the shared example.

name	price	quantity	total_value
Cherries	5	30	150
Apples	2	50	100
Bananas	1	80	80

Identical syntax and result across all engines.

Useful when

Where this command helps.

computing a derived metric like total price or profit margin per row
formatting or transforming values at query time without changing stored data

Explanation

What the command is doing.

Any valid expression can appear in a SELECT list alongside plain column references. Arithmetic operators (+, -, *, /), string functions, CASE expressions, and calls to built-in functions all produce new columns in the result without modifying the underlying table. Giving the computed column a name with AS makes the output readable and lets the alias be referenced in ORDER BY. Note that most databases do not allow a SELECT alias to appear in the same query's WHERE clause — use a subquery or CTE if you need to filter on a computed value.

Select Computed Columns With Expressions

Compute the total stock value for each inventory item

Where this command helps.

What the command is doing.

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