# Specifying Columns

List the columns you want, in the order you want them, and rename them in the result with AS.

Novice · T-SQL · SQL · Updated November 3, 2026

## After this lesson you can

- Choose and rename the columns a query returns

## Key takeaways

- In application code, name the columns you need: less data travels, and the result doesn't change when someone adds a column.
- Columns come back in the order you list them, whatever their order in the table.
- `AS` gives a column an alias, a new name in the result only; the table doesn't change.
- An alias with a space needs square brackets, as in `UnitPrice AS [List Price]`; brackets also allow names such as `[Order]`.

`SELECT *` is handy for exploring, but in application programming it's best to name exactly the columns you need:

```sql
SELECT ProductName, UnitPrice, UnitsInStock
FROM Products;
```

| ProductName | UnitPrice | UnitsInStock |
|---|---|---|
| Chai | 18.00 | 39 |
| Chang | 19.00 | 17 |
| Aniseed Syrup | 10.00 | 13 |
| Chef Anton's Cajun Seasoning | 22.00 | 53 |

Why not just use `*`?

- **Less data travels.** A table can have dozens of columns, some of them large. Your app only pays for what it asks for.
- **The result doesn't change by surprise.** If someone adds a column to the table later, a `SELECT *` suddenly returns it, and code that expected the old columns can break.
- **The query says what it's for.** Anyone reading it sees exactly which data the page uses.

## Choosing the order

The columns come back in the order you list them, whatever their order in the table:

```sql
SELECT City, Country, CompanyName
FROM Customers;
```

Long column lists are often written one per line, with the commas at the start of each line, so a column is easy to add, remove or comment out:

```sql
SELECT CompanyName
    , ContactName
    , City
    , Country
FROM Customers;
```

## Renaming columns with AS

`AS` gives a column a different name in the result, called an **alias**. The table doesn't change; only the heading of the result does:

```sql
SELECT ProductName AS Product
    , UnitPrice AS Price
    , UnitsInStock AS InStock
FROM Products;
```

| Product | Price | InStock |
|---|---|---|
| Chai | 18.00 | 39 |
| Chang | 19.00 | 17 |

An alias with a space in it needs square brackets: `UnitPrice AS [List Price]`. Square brackets also let you use a table or column name that has a space or is a keyword, such as `[Order]` in the BooksPlus database.

## Check yourself

1 question to try on the lesson page.

## So what

Naming your columns makes a query faster, safer and self-explaining, and an alias lets the result use the names your app or your report needs.

## Key terms

- [Column Alias](https://www.ask-codey.com/glossary/column-alias)
- Square Bracket Identifiers

## Cheat sheets

- [Simple SELECT Query and Specifying Columns](https://www.ask-codey.com/cheat-sheets/select-in-t-sql-simple-select-query-cheat-sheet)

Source: https://www.ask-codey.com/lessons/select-in-t-sql-specifying-columns