Can't use a column in a variable

[aflintdepm]

I am trying to create a measure using a variable.  I want the variable to take the value from a column in the same table, so relationship shouldn't be an issue.

When I try to create the variable, the suggested column list suggests almost every column EXCEPT the column I want to use.  If I manually type out the column (with table) it is not recognized.  The column is a non-unique number value, but I need it to calculate per row.  

What are the steps to take to figure out why I can't access this column as a variable?  Most other columns in this table are available to me

[lbendlin · Accepted solution]

measures need aggregations like MAX() or SUM()

[aflintdepm]

I've learned that, but I was only trying to write a variable- any suggestion for why it won't let me use a number column as a variable input?

[lbendlin]

the same rules apply to variables inside a measure.