Microsoft Office Tutorials and References

In Depth Information

**Writing Expressions in Access**

Using functions in expressions

Wait — there’s more. An Access expression can also contain any number of

functions. A
function
is sort of like an operator in that it performs some

calculation and then
returns
some value. The way that you use a function is

different, though: Every function includes a name followed by a pair of parentheses.

The Date() function, for example, always returns the current date.

Many functions accept
arguments,
which are enclosed within the

parentheses. To calculate the square root of a number, you use the Sqr() function.

The Sqr() function accepts one parameter: a number, the name of a field,

or an expression that contains a number. The Sqr() function returns the

square root of whatever value passes to it as an argument.

The following expression returns 9 because the square root of 81 is 9

(because 9 times 9 is 81). In this example, we use a number as the argument

to the Sqr() function:

Sqr(81)

Note that in the example, we use 81 as the argument to the Sqr() function.

Another way to state this is to say that we
pass
the number 81 to the

function. In other words, the term
pass
in this context means “to use as an

argument in a function.”

Book III

Chapter 2

The following Sqr() function uses an expression (5*20) as its argument:

Sqr(5*20)

Because the expression, 5*20, is inside the parentheses, the

multiplication happens first. For an instant, the function contains Sqr(100). Then

Sqr(100) returns 10 because 10 is the square root of 100.

You can use field names in functions as well. Suppose that you have a

table that contains a number field named bigNumber. The following

Sqr() function returns the square root of whatever value is stored in the

bigNumber field:

Sqr([bigNumber])

Dozens of functions are built into Access. In fact, memorizing all the

functions is nearly impossible. We recommend looking up functions as you need

them, using Expression Builder as your guide. What’s Expression Builder?

Read on to find out.