Custom expression language details
If you learn how the custom expression language works, the creation of valid custom expressions will be easier. This topic attempts to explain some basic functionality of the language.
If a column name contains characters other than letters, digits or _ (underscore), then they must be enclosed with "[" and "]" characters (square brackets). The square brackets are also required when the column name is the same as a function name, or when the column name begins with a digit.
If you apply <> around an expression, it is treated as categorical.
Multiple columns are normally separated by a comma.
You can use the AS keyword to specify a new name for an expression in the custom expression dialog, and hide the underlying expression. See below for some examples. Note that when the axis expression contains commas, you cannot rename the entire axis, but you can define one name for each part of the expression.
Constants can always be used as an argument, even if the function description says that the argument has to be a column.
Examples of expressions:
[Column1]/([Column1]+[Column2]) AS Quota
[Column1] AS [My first column], [Column2] AS [My second column]
<[Category column 1]>
<[Category column 1] nest [Category column 2]>
cast (power(2,2) as integer)
case [Column1] when 10 then 'ten' else 'not ten' end
case when Column1 is not null then Column1 else Column2 end