Creates a classification of expressions. The bin width is determined by the number set as interval. The result is shown as a<=x<b, where a and b are the upper and lower limits of the bin. The x can be replaced by an arbitrary string stated in label. 0 is normally the default starting point of the classification. This can be changed by adding an offset.
class( var,10 ) with var = 23 returns '20<=x<30'
class( var,5,'value' ) with var = 23 returns '20<= value <25'
class( var,10,'x',5 ) with var = 23 returns '15<=x<25'
in other words, i want to join the static column "ID" with the dynamically generated column "ID".
Your linked articles concern only how to generate classes. The expression itself is not important, only the fact that i need to join the result of an expression with a static table that was loaded before.