19

I am trying different queries in the Query Builder. Is there a way to comment the query? I tried with

/* */

#

--

without success :

An error occurred when executing the query. The data provider said: OGR[3] error 1: SQL Expression Parsing Error: syntax error

EDIT :

  • I have made a feature request of this question: http://hub.qgis.org/issues/10914

  • @Bernd V. observed that expressions are evaluated differently according to the format of the vector (see the [help] button in the Query builder for more information)

2
  • Welcome to GIS! Unless I'm mistaken, I don't think you can comment queries in the Query Builder.
    – Joseph
    Jul 17, 2014 at 12:18
  • Is there an other way to build queries then (and comment them as required ?) (Thx for editing, it looks much better)
    – nebi
    Jul 17, 2014 at 12:48

2 Answers 2

15

It doesn't work with ESRI shapefile. However, commenting in expressions works in QGIS 2.14 with SpatiaLite, SQlite and GeoPackage. For most other formats available in the Save as...-dialog, the query fails with an OGR-error.

Use -- for one-line comments and /* ... */ for multi-line comments

It turns the letters to a green color in the expression builder window and they seem indeed to be commented out!

8
  • Awesome! I don't have QGIS 2.8.2 to test but it is mentioned here so I believe you :) In which case, your answer should be accepted!
    – Joseph
    Jun 2, 2015 at 12:18
  • and @Joseph: are you sure you're in the Query Builder? I can't reproduce it. It turns the letters to green but it still doesn't work (2.8.2-Wien).
    – nebi
    Jun 4, 2015 at 8:11
  • @nebi - I also cannot reproduce it in the Query Builder (also installed 2.8.2 Wien). Only seems to work in the Field Calculator. Have you opened a ticket (feature request) for this?
    – Joseph
    Jun 4, 2015 at 11:32
  • didn't test it beforehand in the Query Builder (sorry) but with rule based rendering expressions etc, cause I hardly ever use that thing. But here it works as well. Am on Linux Mint, maybe there is a difference/bug in Windows?
    – Bernd V.
    Jun 4, 2015 at 12:22
  • Ha! Seems I found the difference. I was using it successfully with a Spatialite-Layer. Now I tested it with a ESRI-Shape ... and it fails!
    – Bernd V.
    Jun 4, 2015 at 12:36
6

You can build queries by using the Query Builder or an alternative is to use the Expression string builder (Layer Properties > Style > select Rule-based > add a rule > insert your command in the Filter box or click the '...' button to bring up the string builder interface.

In both cases, I do not think QGIS supports the comments function when creating expressions for filters/queries:

http://docs.qgis.org/testing/en/docs/pyqgis_developer_cookbook/expressions.html

3
  • True, with this way you can save your rules and import / export them ... But it's not as quick as commenting with some symbol at the beginning of the line. Copy / paste in the query Builder is tedious
    – nebi
    Jul 17, 2014 at 13:58
  • 2
    @nebi, you could always send a request for this to be implemented in future updates.
    – Joseph
    Jul 17, 2014 at 14:11
  • Yes, I want to do it
    – nebi
    Jul 17, 2014 at 14:12

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