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I am trying to categorise my site points by species group with rule based symbology;

e.g. bat uses the formula

"Group"='Bat'

But I would also like to have a different symbol for where there are no bats recorded at that site (i.e. based on the abundance in a separate column which is taken from a join with another table). I have tried this below but it hasn't worked, does anyone know how to fix this?

"Group"='Bat' AND "records_Abundance" = '<= 0' (for sites where species not present)

"Group"='Bat' AND "records_Abundance" = '>= 1' (for sites where species are present)

It seems to only read the abundance part and either turns all my points for all species to the symbol or none at all?

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    I'd rather use if(records_Abundance LIKE '<=0',0,2) as condition for the size of the point-symbol - it gives no symbol, when the amount of bats is 0, else it gives a symbol 2 units wide. Also, for me CASE WHEN group='Bat' AND records='<= 0' THEN TRUE END does work - as well as any variations with spaces and/or quotation marks. – Erik Nov 12 at 12:26
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    just use "Group"='Bat' AND "records_Abundance" = '<= 0' without CASE WHEN – eurojam Nov 12 at 12:27
  • It still doesn't work. the records_Abundance column is from a join from a different table, is this a problem? Because I don't know what else might be wrong with it? – Janine McMahon Nov 12 at 12:33
  • Also, I need a symbol for the project site for if it does or does not have species present so have two different symbology expressions for each because they will have different symbols – Janine McMahon Nov 12 at 12:36
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    @JanineMcMahon - You could create a new field and copy the values over from the joined field by using the name of the field as the expression (e.g. "records_Abundance"). – Joseph Nov 13 at 10:24
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"Group"='Bat' AND "records_Abundance" <= 0 (for sites where species not present)
"Group"='Bat' AND "records_Abundance" >= 1 (for sites where species are present)

do not need the <= or >= in quotations

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