# Error while trying to use conditionnal

**URL:** <https://community.influxdata.com/t/error-while-trying-to-use-conditionnal/24534>\
**Category:** Fluxlang\
**Created:** [April 5, 2022, 2:34pm UTC](https://community.influxdata.com/t/error-while-trying-to-use-conditionnal/24534 "2022-04-05T14:34:11Z")\
**Posts on this page:** 10\
**Page:** 1

<div class="post-metadata">

**Author:** ![Tiki10](https://sea1.discourse-cdn.com/flex023/user_avatar/community.influxdata.com/tiki10/32/9735_2.png) [@Tiki10](https://community.influxdata.com/u/Tiki10)\
**Post date:** [April 5, 2022, 2:34pm UTC](https://community.influxdata.com/t/error-while-trying-to-use-conditionnal/24534/1 "2022-04-05T14:34:11Z")

</div>

Hello,

I’m trying to automate bytesIn measurement from interface depending of my router’s model.  
I wrote this query where $hostname and $model are already defined and working:

```auto
> from(bucket: "telegraf/autogen")
> |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
> |> filter(fn: (r) => r["hostname"] == "$hostname")
> |> filter(fn: (r) => r["_field"] == "${Model}")
> |> filter(fn: (r) => if ${Model} == "RouterOS RBD53GR-5HacD2HnD" then
> r._measurement == "snmp_interfaces" and r.hostname == "${hostname}" and r.if-name == "lte1" and r._field == "bytesIn"
> else
> r._measurement == "snmp_interfaces" and r.hostname == "${hostname}" and r.if-name == "ether1" and r._field == "bytesIn",
> )
> |> map(fn: (r) => ({r with _value: r._value *8}))
> |> derivative(unit: 1s, nonNegative: false)
> |> yield(name: "derivative")

```

This is not working, I have this error:  
`invalid: compilation failed: error at @6:21-6:22: expected THEN, got IDENT (RB2011UiAS) at 5:36 error at @6:21-6:22: expected THEN, got SUB (-) at 5:46 error at @6:21-6:22: expected THEN, got INT (2) at 5:47 error at @6:21-6:22: expected THEN, got IDENT (HnD) at 5:48 error at @6:21-6:22: expected THEN, got EQ (==) at 5:52 error at @6:21-6:22: expected THEN, got STRING ("RouterOS RBD53GR-5HacD2HnD") at 5:55 error at @6:108-6:112: expected IDENT, got IF (if) at 6:105 error at @6:108-6:112: expected IDENT, got SUB (-) at 6:107 error at @8:108-8:112: expected IDENT, got IF (if) at 8:105 error at @8:108-8:112: expected IDENT, got SUB (-) at 8:107`

What I doing wrong ?

Regards,

---

<div class="post-metadata">

**Author:** ![scott](https://sea1.discourse-cdn.com/flex023/user_avatar/community.influxdata.com/scott/32/16492_2.png) [@scott](https://community.influxdata.com/u/scott)\
**Post date:** [April 5, 2022, 3:02pm UTC](https://community.influxdata.com/t/error-while-trying-to-use-conditionnal/24534/2 "2022-04-05T15:02:34Z")

</div>

@Tiki10 One error I see is that you need to wrap `${Model}` in your conditional in quotes. I’m wondering if that will fix the rest of the errors.

```diff
- |> filter(fn: (r) => if ${Model} == //...
+ |> filter(fn: (r) => if "${Model}" == //...

```

---

<div class="post-metadata">

**Author:** ![Tiki10](https://sea1.discourse-cdn.com/flex023/user_avatar/community.influxdata.com/tiki10/32/9735_2.png) [@Tiki10](https://community.influxdata.com/u/Tiki10)\
**Post date:** [April 5, 2022, 5:00pm UTC](https://community.influxdata.com/t/error-while-trying-to-use-conditionnal/24534/3 "2022-04-05T17:00:21Z")

</div>

Hello Scott,

Thank you for your reply.  
I have tested with your syntax and I have another error:  
`invalid: compilation failed: error at @6:109-6:113: expected IDENT, got IF (if) at 6:106 error at @6:109-6:113: expected IDENT, got SUB (-) at 6:108 error at @8:109-8:113: expected IDENT, got IF (if) at 8:106 error at @8:109-8:113: expected IDENT, got SUB (-) at 8:108`

As “$model” is already defined in variable like that:

```auto
from(bucket: "telegraf/autogen")
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => r["_measurement"] == "snmp")
  |> filter(fn: (r) => r["hostname"] == "${hostname}")
  |> filter(fn: (r) => r["_field"] == "Modèle")
  |> aggregateWindow(every: v.windowPeriod, fn: distinct, createEmpty: false)

```

I’ve tried with this query:

```auto
from(bucket: "telegraf/autogen")
   |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
   |> filter(fn: (r) => if "${Model}" == "RouterOS RBD53GR-5HacD2HnD" then
                     r._measurement == "snmp_interfaces" and r.hostname == "${hostname}" and r.if-name == "lte1" and r._field == "bytesIn"
                     else
                     r._measurement == "snmp_interfaces" and r.hostname == "${hostname}" and r.if-name == "ether1" and r._field == "bytesIn",
                    )
   |> map(fn: (r) => ({r with _value: r._value *8}))
   |> derivative(unit: 1s, nonNegative: false)
   |> yield(name: "derivative")

```

And I have a similar error:  
`invalid: compilation failed: error at @4:109-4:113: expected IDENT, got IF (if) at 4:106 error at @4:109-4:113: expected IDENT, got SUB (-) at 4:108 error at @6:109-6:113: expected IDENT, got IF (if) at 6:106 error at @6:109-6:113: expected IDENT, got SUB (-) at 6:108`

Regards,

---

<div class="post-metadata">

**Author:** ![scott](https://sea1.discourse-cdn.com/flex023/user_avatar/community.influxdata.com/scott/32/16492_2.png) [@scott](https://community.influxdata.com/u/scott)\
**Post date:** [April 5, 2022, 5:04pm UTC](https://community.influxdata.com/t/error-while-trying-to-use-conditionnal/24534/4 "2022-04-05T17:04:26Z")

</div>

Ah, I needed to scroll over more 😄. Right now, `r.if-name` is being parsed as a conditional statement and an arithmetic operation (`-`). Becuase you have a dash in the property key, you need to use bracket notation instead of dot notation.

Try this:

```javascript
from(bucket: "telegraf/autogen")
   |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
   |> filter(fn: (r) => if "${Model}" == "RouterOS RBD53GR-5HacD2HnD" then
                     r._measurement == "snmp_interfaces" and r.hostname == "${hostname}" and r["if-name"] == "lte1" and r._field == "bytesIn"
                     else
                     r._measurement == "snmp_interfaces" and r.hostname == "${hostname}" and r["if-name"] == "ether1" and r._field == "bytesIn",
                    )
   |> map(fn: (r) => ({r with _value: r._value *8}))
   |> derivative(unit: 1s, nonNegative: false)

```

---

<div class="post-metadata">

**Author:** ![Tiki10](https://sea1.discourse-cdn.com/flex023/user_avatar/community.influxdata.com/tiki10/32/9735_2.png) [@Tiki10](https://community.influxdata.com/u/Tiki10)\
**Post date:** [April 6, 2022, 10:04am UTC](https://community.influxdata.com/t/error-while-trying-to-use-conditionnal/24534/5 "2022-04-06T10:04:45Z")

</div>

> [@scott](#):
>
> ```auto
> from(bucket: "telegraf/autogen")
> |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
> |> filter(fn: (r) => if "${Model}" == "RouterOS RBD53GR-5HacD2HnD" then
> r._measurement == "snmp_interfaces" and r.hostname == "${hostname}" and r["if-name"] == "lte1" and r._field == "bytesIn"
> else
> r._measurement == "snmp_interfaces" and r.hostname == "${hostname}" and r["if-name"] == "ether1" and r._field == "bytesIn",
> )
> |> map(fn: (r) => ({r with _value: r._value *8}))
> |> derivative(unit: 1s, nonNegative: false)
> 
> ```

Hello Scott,

Thank you for your time, patience and advices.  
Syntax was, indeed, the problem.  
Now, I have another error : invalid: runtime error @3:7-7:22: filter: type conflict: int != string  
There is a way to have something like “echo” or “var\_dump”. I’d like to have \_value’s return. \_value should be an integer and it seems to be a string.

Regards,

---

<div class="post-metadata">

**Author:** ![scott](https://sea1.discourse-cdn.com/flex023/user_avatar/community.influxdata.com/scott/32/16492_2.png) [@scott](https://community.influxdata.com/u/scott)\
**Post date:** [April 6, 2022, 3:09pm UTC](https://community.influxdata.com/t/error-while-trying-to-use-conditionnal/24534/6 "2022-04-06T15:09:38Z")

</div>

I don’t think this is an error related to the type of your `_value` column. I think it’s an error related to the types used in your predicate. What version of InfluxDB / Flux are you using? I’m wondering if you’re using and older version of Flux that doesn’t automatically interpolate numeric values in strings (fixed in Flux 0.109) and your `Model` variable is actually an integer. If that’s the case, try this:

```javascript
// ...
   |> filter(fn: (r) => if "${string(v: Model)}" == "RouterOS RBD53GR-5HacD2HnD" then
// ...

```

---

<div class="post-metadata">

**Author:** ![Tiki10](https://sea1.discourse-cdn.com/flex023/user_avatar/community.influxdata.com/tiki10/32/9735_2.png) [@Tiki10](https://community.influxdata.com/u/Tiki10)\
**Post date:** [April 7, 2022, 7:03am UTC](https://community.influxdata.com/t/error-while-trying-to-use-conditionnal/24534/7 "2022-04-07T07:03:17Z")

</div>

Hello Scott,

Influx version 's return is :  
root@poc ~ $ influx version  
Influx CLI 2.2.1 (git: 31ac783) build\_date: 2021-11-09T21:24:22Z

With:

```auto
from(bucket: "telegraf/autogen")
   |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
   |> filter(fn: (r) => if "${string(v: ${Model})}" == "RouterOS RBD53GR-5HacD2HnD" then
                     r._measurement == "snmp_interfaces" and r.hostname == "${hostname}" and r["if-name"] == "lte1" and r._field == "bytesIn"
                     else
                     r._measurement == "snmp_interfaces" and r.hostname == "${hostname}" and r["if-name"] == "ether1" and r._field == "bytesIn"
                    )
   |> map(fn: (r) => ({r with _value: r._value * 8}))
   |> derivative(unit: 1s, nonNegative: false)

```

I have this error:  
`invalid: error @3:41-3:49: undefined identifier RouterOS error @3:50-3:57: undefined identifier RBD53GR error @3:41-3:59: invalid binary operator <INVALID_OP> error @3:59-3:67: undefined identifier HacD2HnD error @3:41-3:67: invalid binary operator <INVALID_OP>`

So I think that the minus symbol in RouterOS RBD53GR-5HacD2HnD is (again) the problem.

Regards

---

<div class="post-metadata">

**Author:** ![scott](https://sea1.discourse-cdn.com/flex023/user_avatar/community.influxdata.com/scott/32/16492_2.png) [@scott](https://community.influxdata.com/u/scott)\
**Post date:** [April 7, 2022, 3:09pm UTC](https://community.influxdata.com/t/error-while-trying-to-use-conditionnal/24534/8 "2022-04-07T15:09:01Z")

</div>

@Tiki10 remove the string interpolation around `Model`:

```diff
- |> filter(fn: (r) => if "${string(v: ${Model})}" == "RouterOS RBD53GR-5HacD2HnD" then
+ |> filter(fn: (r) => if "${string(v: Model)}" == "RouterOS RBD53GR-5HacD2HnD" then
```

---

<div class="post-metadata">

**Author:** ![Tiki10](https://sea1.discourse-cdn.com/flex023/user_avatar/community.influxdata.com/tiki10/32/9735_2.png) [@Tiki10](https://community.influxdata.com/u/Tiki10)\
**Post date:** [April 22, 2022, 9:54am UTC](https://community.influxdata.com/t/error-while-trying-to-use-conditionnal/24534/9 "2022-04-22T09:54:17Z")

</div>

Hello Scott,

Sorry for the long time to reply.  
I’ve tried without interpolation like that

```auto
from(bucket: "telegraf/autogen")
   |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
   |> filter(fn: (r) => if "${string(v: Model)}" == "RouterOS RBD53GR-5HacD2HnD" then
                     r._measurement == "snmp_interfaces" and r.hostname == "${hostname}" and r["if-name"] == "lte1" and r._field == "bytesIn"
                     else
                     r._measurement == "snmp_interfaces" and r.hostname == "${hostname}" and r["if-name"] == "ether1" and r._field == "bytesIn"
                    )
   |> map(fn: (r) => ({r with _value: r._value * 8}))
   |> derivative(unit: 1s, nonNegative: false)

```

The error is now : Undefined idnetifier Model

Regards

---

<div class="post-metadata">

**Author:** ![Tiki10](https://sea1.discourse-cdn.com/flex023/user_avatar/community.influxdata.com/tiki10/32/9735_2.png) [@Tiki10](https://community.influxdata.com/u/Tiki10)\
**Post date:** [April 22, 2022, 1:18pm UTC](https://community.influxdata.com/t/error-while-trying-to-use-conditionnal/24534/10 "2022-04-22T13:18:59Z")

</div>

Hello,

I reimagined the way to have a dynamic interface then I change the Interface’s variable query instead of trying the add it in each dashboard query in Grafana, and, it works !  
I’ve used your first reply like that:

```auto
from(bucket: "telegraf/autogen")
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => r["_measurement"] == "snmp_interfaces")
  |> filter(fn: (r) => r["hostname"] == "${hostname}")
  |> pivot(rowKey:["_time"], columnKey: ["_field"], valueColumn: "_value")
  |> group()
  |> distinct(column: "if-name")
  |> filter(  
      fn: (r) => if "${Model}" == "RouterOS RBD53GR-5HacD2HnD" then
          r._value == "lte1"
      else
          r._value == "ether1",
    )

```

I don’t know why it’s working in Variables setting and not in Dashboard Queries.

Regards,

Vincent