Show trailing zeros in rounded concatenated labels

Question

I'm currently rounding my labels in QGIS using

 round(field_4,1)

in simple labels. This works great, but if the number is rounded to, say, 52.0 it shows as 52 instead. This is easily fixed for non-concacenated labels by enabling the following option in formatting (translation from danish: formatted numbers, decimalspaces):

This however doesn't seem to work for my concatenated labels shown below:

field_1 ||  '\n'  || '+' ||  round( field_4,1)

Is there a way to force QGIS to show trailing zeros?

Answer 1

You can make use of format_number and force it to have 1 decimal.