Creating an Expression

See Also      Tasks

An expression consists of any combination of column names, literals, operators, or functions. Follow these guidelines in combining elements to form expressions:

The following table illustrates the use of expressions in a query.

Expression1 Result
SELECT (price * .9)
FROM products
Displays a discounted price (10% off the value in the price column).
SELECT (lname + ', ' + fname)
FROM employee
Displays the concatenated values of the last name and first name columns with a comma between them.
SELECT sales.qty, titles.price

FROM sales INNER JOIN titles ON
sales.title_id = titles.title_id
ORDER BY
(sales.qty * titles.price)

After joining two tables, sorts the result set by the total value of an order (quantity times price).
SELECT au_lname, au_fname
FROM authors
WHERE
(SUBSTRING(phone, 1, 3) = '415')
Displays authors whose area code is in the San Francisco area.
SELECT ord_num, ord_date
FROM sales
WHERE
(ord_date >=
  DATEADD(day, -10, GETDATE()))
Finds all orders in the sales table that were made in the last 10 days. Today’s date is returned by the GETDATE( ) function.

1Some of the operators and functions shown here are specific to one database. For details about what operators and functions you can use, refer to the documentation for your database.