QGIS rule-based symbology problem

Question

In this project (using QGIS 3.18.1) the filter "veg_actu1" = '600000' or "veg_actu1" = '601000' or "veg_actu1" = '601100' or "veg_actu1" = '602000' or "veg_actu1" = '603000' does not work properly (white areas should be rendered)

If the filter is replaced by regexp_match(veg_actu1, '(600000|601000|601100|602000|603000)') or by case when "veg_actu1" in ('600000','601000','601100','602000','603000') then 1 end it works fine. What am I missing?

Here is a link to the project: https://drive.google.com/file/d/1slBl3b2Pd8yqDFqE4RW7L3bstAujg7dU/view?usp=sharing

If only this rule is on, display is correct.

Answer 1

There may be trailing or leading spaces - as @JGH pointed out. Try using this expression:

trim("veg_actu1") LIKE '600000' or trim("veg_actu1") LIKE '601000' or trim("veg_actu1") LIKE '601100' or trim("veg_actu1") LIKE '602000' or trim("veg_actu1") LIKE '603000'

and see if you get the proper results

Answer 2

There are several ways to solve your problem, one involving other field-format and four avoiding the problematic or operator:

1. Use numbers, not strings - the solution closest to what you have
2. Use like functions - the easiest an most elegant solution
3. Use case condition - the classic solution for such combined conditions
4. Use if condition - works, but a bit more complicated
5. Use in operator -tribute to @jdavid05's comment

In detail:

1. Simply leave away the single quotes: as you don't have texts, but numbers, they are not necessary - thus not "veg_actu1"='600000', but "veg_actu1"=600000 :

   "veg_actu1" = 600000 or "veg_actu1" = 601000 or "veg_actu1" = 601100 or "veg_actu1" = 602000 or "veg_actu1" = 603000

2. function like, used with wildcards (underscores: _)

    "veg_actu1" like '60____'

3. case-condition:

    CASE 
    WHEN "veg_actu1" = '600000' then 1
    WHEN "veg_actu1" = '601000' then 1
    WHEN "veg_actu1" = '602000' then 1
    WHEN "veg_actu1" = '601100' then 1
    WHEN "veg_actu1" = '603000' then 1
    else 0
    end

4. if-condition:

if (
    "veg_actu1" = '601100',1,
        if (
            "veg_actu1" = '600000', 1,
                if (
                    "veg_actu1" = '601000', 1,
                        if (
                            "veg_actu1" = '602000', 1,
                                if ( 
                                    "veg_actu1" = '603000',1,0
                                )
                        )
                )
        )
)

5. in-operator (as proposed in the comment by user @jdavid05)

"veg_actu1" IN ('601100','600000','601000','602000','603000') 

---

Background

After some testing, it turns out that the order of the original expression you used plays a role:

This expression returns styling for some, but not all polygons:

"veg_actu1" = '600000' or "veg_actu1" = '601000' or "veg_actu1" = '602000' or "veg_actu1" = '601100' or "veg_actu1" = '603000'

But with this expression, no polygon at all gets styled:

"veg_actu1" = '601100' or "veg_actu1" = '600000' or "veg_actu1" = '601000' or "veg_actu1" = '602000'  or "veg_actu1" = '603000'

I think the problem is linking several or opeartors one after the other. The help says:

Operator OR: Returns 1 when condition a and b are true.

The examples in the help are like this:

• 4 = 2+2 OR 1 = 1 → 1
• 4 = 2+2 OR 1 = 2 → 1
• 4 = 2 OR 1 = 2 → 0

But you have not something like A OR B, but A OR B OR C OR D OR E. This seems to be problematic, at least when used with strings.