WHERE Clause Expressions

Expressions that compute values from one or more columns can be used advantageously in the WHERE clause of a query. Any legal arithmetic expression involving columns, constants, functions and arithmetic operators (+, -, * and /) is permitted in a WHERE clause. Parentheses may be used as necessary to define evaluation order.

Note:

If null values appear in an expression the result will be null.

The following query is an example of an expression appearing in the WHERE clause of a query:

SELECT pno, weight FROM part
  WHERE city = "LONDON"
    AND weight * 2 > 25