I have a number of expressions in my legend of the following type to show proportions of a total and label them as a percentage of that total, eg:

19th century ([%round(aggregate(layer:='Dwelling_Other',aggregate:='count', expression:="Cons_Yr", filter:=("Locality" IN ('Archies Creek') AND "Cons_Yr" >= 1801 AND "Cons_Yr" <= 1900))/aggregate(layer:='Dwelling_Other',aggregate:='count', expression:="Cons_Yr", filter:=("Locality" IN ('Archies Creek') AND "Cons_Yr" >= 1801))*100)%]%)

These results and labels show correctly in the legend:

enter image description here

until clicking another item or opening another legend item, when they revert to displaying the expression itself instead: enter image description here

If I go back into a legend item and just backspace one or two characters, then it and all the other legend items revert back to showing the result. Is there a way to prevent this from happening?

1 Answer 1


I think it could be because of the ( followed by [. There is also a second % in the end of your formula. Expression should be surrounded by [% and %].

First delete the last %.

Then delete the parenthesis around your expression and add the parenthesis in the expression formula. You can use the formula below as an example :

19th century 
[% '(' || 
   round(aggregate(layer:='Dwelling_Other',aggregate:='count', expression:="Cons_Yr", filter:=("Locality" IN ('Archies Creek') AND "Cons_Yr" >= 1801 AND "Cons_Yr" <= 1900))
   aggregate(layer:='Dwelling_Other',aggregate:='count', expression:="Cons_Yr", filter:=("Locality" IN ('Archies Creek') AND "Cons_Yr" >= 1801))*100)
|| ')'%] 

NB : The || will work only if your number have parentesis around or if it is converted to text with to_string()

  • 1
    Thankyou Corentin. You are right, but those extra bits get appended by QGIS once I leave the expression window. I tried using the same expression in just a simple text label and there it is fine, so now I am inclined to think the issue is with using such an expression in the legend.
    – Funzo
    Commented Mar 17, 2022 at 1:51

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