Just seeing the name of a built-in function in the third column of the Access 2013 Expression Builder doesn't tell you much. You don't know what the function does or how you use it, but you can get instant information by clicking the Help button. Follow these steps to access an Access help window:
In the left column of Expression Builder, if the Functions folder has a plus sign (+) next to it, click that sign to expand the list.
Click the Built-In Functions folder in the first column.
The category names appear in the center column.
Click a category name in the middle column to see functions within that category listed in the third column, or click
in the middle column to see all functions in the third column. The functions for that category appear in the third column.
In the third column, click the name of the function that you want to find out more about.
Click the Help button in the top-right corner of Expression Builder.
The help window for that function opens.
If you don't see specific help for the function, type the function name in the Access Help search box.
Functions are listed by type in the help system, so if you need to find a function in the help system, you'll be able to find it quicker if you know that if it's a Financial function, for example.
To see how this works, select the Financial category of functions in the center column, click the PV function in the third column, and then click the Help button. The help page that opens not only describes what the PV function does, but also describes the syntax required for using the function. The syntax of a function describes what information you need to pass (provide) to the function for the function to do its calculation and return a result.
The syntax for a function usually looks something like the following:
functionName(arg1,arg2,[arg3])
functionName is the name of the function, and arg1, arg2, and arg3 represent arguments that the function accepts. The number of arguments that a function accepts varies. Some functions take no arguments; others take many. If a function accepts two or more arguments, the arguments must be separated by commas.
Any argument name in square brackets is optional, meaning that you can omit the entire argument.
A function name is always followed by parentheses — even if the function accepts no arguments. Now(), Sqr(81), and PV(apr,TotPmts,Income) are all examples of valid function syntax. Note as well that when typing an argument, you can use a literal value (like the name "Smith" or the number 10), a field name, or an expression as an argument. The following three expressions all pass literal values to their functions:
Sqr(100) PV(.035,120,250) UCase("howdy")
The next three expressions all pass data from fields to the function (provided that Hypot, Apr, Months, Amount, and Company are the names of fields in the current query):
Sqr([Hypot]) PV([Apr],[Months],[Amount]) UCase([Company])
The next example uses expressions as arguments:
Sqr(227*[Hypot]) PV([Apr]/12,[Months]*12,-1*[Amount]) UCase([First Name] & " " & [Last Name])
These examples may look weird, but there's method to the madness. The ability to pass literal data, field names, and/or expressions to functions gives you a lot of flexibility.