# Join producing no output

**URL:** <https://community.riskscape.org.nz/t/join-producing-no-output/139>\
**Category:** Community\
**Created:** [27 July 2023 03:45 UTC](https://community.riskscape.org.nz/t/join-producing-no-output/139 "2023-07-27T03:45:33Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![JPowell](https://avatars.discourse-cdn.com/v4/letter/j/bbce88/32.png) [@JPowell](https://community.riskscape.org.nz/u/JPowell)\
**Post date:** [27 July 2023 03:45 UTC](https://community.riskscape.org.nz/t/join-producing-no-output/139/1 "2023-07-27T03:45:33Z")

</div>

I am trying to join 2 files but Riskscape is returning an empty file as output

project.ini

```auto
[model addProbs]
description = takes an SSP pathway and year and adds to the output from addSSPIds
location = addProbabilties.txt
framework = pipeline

```

addProbabilities.txt

```auto
input('SSPFull.csv') as allSSPs
-> filter("year" = '2040')
-> filter("measurementName" = 'SSP5-8.5 (low confidence)')
-> filter("siteId" = '689')

-> SSP_join.rhs

input('AAL_High_sspid.csv', name: 'AALs')
->
join(on: 'AALs.hazard_coverage_siteId' = "siteId") as SSP_join
->
save(name: 'output')

```

SSPFull.csv

```auto
"siteId","year","p17","p50","p83","lon","lat","measurementName"
"689",2040,0.14,0.18,0.29,174.6772,-36.6197,"SSP5-8.5 (low confidence)"

```

AAL\_High\_sspid.csv

```auto
hazard_coverage_siteId,hazard_coverage.lat,hazard_coverage.lon,hazard_coverage.geom
689,0,0,0

```

```auto
C:\Users\powellj\>riskscape model run addProbs
[WARNING] A Java upgrade is recommended. Your computer is currently using Java version 11.0.19, which will no longer be supported by future versions of RiskScape (RiskScape v1.5.0 onwards). Please upgrade to Java 17 (or higher) to ensure RiskScape will continue to run on your computer.
[WARNING] The 'beta' plugin is enabled. This contains experimental features that may significantly change or be deprecated in future releases.
[WARNING] No output has been produced from pipeline step(s) 'SSP_join:[join]'. Possible causes may be: the pipeline uses a filter condition that does not match any data; the model uses a join condition based on geometry, but the datasets do not overlap geographically; or for CSV-based data, the incorrect CRS (or `crs-longitude-first`) bookmark setting is being used.
file:/C:/Users/powellj/output/addProbs/2023-07-27T15_36_40/output.csv

```

The warning says that the filter step might be removing all data but if I run the pipeline with everything after → filter(“siteId” = ‘689’) commented out it works fine and returns the expected rhs.

---

<div class="post-metadata">

**Author:** ![timbeale](https://avatars.discourse-cdn.com/v4/letter/t/57b2e6/32.png) [@timbeale](https://community.riskscape.org.nz/u/timbeale)\
**Post date:** [27 July 2023 04:04 UTC](https://community.riskscape.org.nz/t/join-producing-no-output/139/2 "2023-07-27T04:04:22Z")

</div>

I think the problem is the left-hand side of the join condition uses singe-quotes, so it’s being treated as a literal text-string:

```auto
join(on: 'AALs.hazard_coverage_siteId' = "siteId") as SSP_join

```

Just remove the single-quotes and the join should start matching things correctly, i.e.

```auto
join(on: AALs.hazard_coverage_siteId = "siteId") as SSP_join

```

---

<div class="post-metadata">

**Author:** ![JPowell](https://avatars.discourse-cdn.com/v4/letter/j/bbce88/32.png) [@JPowell](https://community.riskscape.org.nz/u/JPowell)\
**Post date:** [27 July 2023 04:11 UTC](https://community.riskscape.org.nz/t/join-producing-no-output/139/3 "2023-07-27T04:11:41Z")

</div>

Thanks Tim that has worked. In the actual pipeline the column name is

```auto
hazard_coverage.siteId

```

I cant find a combination of quotes that allows me to have that dot in there. Is it possible?

```auto
Failed to validate model for execution
  - Failed to validate 'join(on: AALs.hazard_coverage.siteId = "siteId") as SSP_join' step for execution
    - Could not find 'AALs.hazard_coverage.siteId' among [AALs.hazard_coverage.siteId, AALs.hazard_coverage.lat, AALs.hazard_coverage.lon, AALs.hazard_coverage.geom, siteId, year, p17, p50, p83, lon, lat, measurementName]

```

---

<div class="post-metadata">

**Author:** ![timbeale](https://avatars.discourse-cdn.com/v4/letter/t/57b2e6/32.png) [@timbeale](https://community.riskscape.org.nz/u/timbeale)\
**Post date:** [27 July 2023 04:14 UTC](https://community.riskscape.org.nz/t/join-producing-no-output/139/4 "2023-07-27T04:14:17Z")

</div>

Yes, it’s possible, but the syntax starts getting a little tricky. Try this:

```auto
join(on: AALs."hazard_coverage.siteId" = siteId) as SSP_join

```

---

<div class="post-metadata">

**Author:** ![timbeale](https://avatars.discourse-cdn.com/v4/letter/t/57b2e6/32.png) [@timbeale](https://community.riskscape.org.nz/u/timbeale)\
**Post date:** [27 July 2023 04:52 UTC](https://community.riskscape.org.nz/t/join-producing-no-output/139/5 "2023-07-27T04:52:42Z")

</div>

Here’s my attempt at explaining what’s going on here a little more.

Unlike Python, double-quotes behave quite differently to single-quotes in a RiskScape pipeline. Double-quotes are only ever used for identifiers (i.e. attribute names). In particular, they’re used to escape other special characters. For example, the expression `5--8.5` would evaluate to 13.5, whereas the expression `"5--8.5"` would be treated as an attribute name (i.e. a CSV column called `5--8.5`).

In a RiskScape expression, `.` is an _operator_ (similar to how `+` or `-` are operators). It references an attribute within a struct. Double-quotes will escape this behaviour, the same way they do for `+` and `-`.

So in your example pipeline:

- `'AALs.hazard_coverage_siteId'` is just a text-string literal (same as in Python code)
- `AALs.hazard_coverage_siteId` is referencing the `hazard_coverage_siteId` attribute from the `AALs` struct. Here all the attributes from the AAL\_High\_sspid.csv file are wrapped up in a `AALs` struct.
- `"AALs.hazard_coverage_siteId"` is a _single_ attribute with a `.` in the name. You can use special characters like this in pipeline attribute names, but they need to be enclosed in double-quotes so that RiskScape doesn’t try to interpret them as some other kind of expression.
- `AALs."hazard_coverage.siteId"` is referencing the `"hazard_coverage.siteId"` attribute from the `AALs` struct. Because this attribute has a `.` in the name, it needs to be escaped with double-quotes (but the first `.` in the ‘`AALs.`’ bit needs to sit outside the double-quotes, so that the `.` operator still takes effect).

Basically, it’s simplest to avoid `.` in attribute names and then you don’t have to worry about double-quotes at all. However, we need to fix up writing CSV files (and probably GeoJSON too), so they don’t include the '`.`'s in the attribute names.

In the meantime, the `.*` ‘splat’ operator might be handy. It pulls all of the attributes out of a struct, so it effectively gets rid of the `.` in the attribute names. E.g. in your pipeline where you generate the `AAL_High_sspid.csv` file, you could add the following step before you save the results, which would remove the ‘`hazard_coverage.`’ bit from the CSV column names.

```auto
 ->
select({ hazard_coverage.* })
 ->
save('AAL_High_sspid', format: 'csv')

```