# Calculations in Columns

Work out new values as you query, with arithmetic on a row's columns and joined text, and give each calculated column a name.

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

## After this lesson you can

- Calculate a new column from the values in each row

## Key takeaways

- A calculated column works out a value from the columns in the same row, such as `UnitPrice * UnitsInStock`.
- Always give a calculation an alias with `AS`, or it comes back with no column name.
- As in C#, dividing one whole number by another drops the remainder: `7 / 2` is 3, and `7 / 2.0` keeps the decimals.
- `+` joins text, and text goes in single quotes, as in `FirstName + ' ' + LastName`.
- `CONCAT` joins text too, and also takes numbers, such as `UnitsInStock`, and empty values without errors.

A query can return more than the stored columns: it can calculate new values as it goes. Each calculation uses the values **in the same row**.

## Arithmetic

How much stock of each product does the company hold, in dollars? Multiply the price by the units in stock:

```sql
SELECT ProductName
    , UnitPrice
    , UnitsInStock
    , UnitPrice * UnitsInStock AS StockValue
FROM Products;
```

| ProductName | UnitPrice | UnitsInStock | StockValue |
|---|---|---|---|
| Chai | 18.00 | 39 | 702.00 |
| Chang | 19.00 | 17 | 323.00 |
| Aniseed Syrup | 10.00 | 13 | 130.00 |
| Chef Anton's Cajun Seasoning | 22.00 | 53 | 1166.00 |

Without `AS StockValue`, the calculated column would have no name at all; SSMS shows it as *(No column name)*. Always give a calculation an alias.

The operators are the ones you know from C#: `+`, `-`, `*`, `/` and `%`. And as in C#, dividing one whole number by another drops the remainder: `7 / 2` is `3`. Write `7 / 2.0` to keep the decimals.

## A line total

Each row of `OrderDetails` is one product on one order. Its total is the price times the quantity:

```sql
SELECT OrderId
    , ProductId
    , UnitPrice
    , Quantity
    , UnitPrice * Quantity AS LineTotal
FROM OrderDetails;
```

| OrderId | ProductId | UnitPrice | Quantity | LineTotal |
|---|---|---|---|---|
| 10248 | 11 | 14.00 | 12 | 168.00 |
| 10248 | 42 | 9.80 | 10 | 98.00 |
| 10248 | 72 | 34.80 | 5 | 174.00 |

## Joining text

`+` also joins text, as it does in C#:

```sql
SELECT FirstName + ' ' + LastName AS EmployeeName
    , Title
FROM Employees;
```

| EmployeeName | Title |
|---|---|
| Nancy Davolio | Sales Representative |
| Andrew Fuller | Vice President, Sales |

Text in SQL goes in **single** quotes: `' '` is a space. (Double quotes mean something else in SQL, so avoid them for text.)

`CONCAT` joins text too, and it also handles numbers and empty values without errors:

```sql
SELECT CONCAT(ProductName, ' (', UnitsInStock, ' in stock)') AS Label
FROM Products;
```

| Label |
|---|
| Chai (39 in stock) |
| Chang (17 in stock) |

## Check yourself

2 questions to try on the lesson page.

## So what

Calculated columns let the database hand you finished numbers and labels, so your app shows them instead of working them out itself.

## Key terms

- [Calculated Column](https://www.ask-codey.com/glossary/calculated-column-sql)
- [String Literal](https://www.ask-codey.com/glossary/string-literal)
- String Functions

## Cheat sheets

- [Calculations in Columns](https://www.ask-codey.com/cheat-sheets/select-in-t-sql-calculations-in-columns-cheat-sheet)

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