4

Using QGIS 2.16.2 I would like to export the unique values in a shapefile string attribute field to a new database table (which would contain a single field listing the unique values). The Vector > Analysis Tools > List Unique Values tool correctly selects the unique values, but the only output option is an .html file. Is there some way to output to a .dbf, or .csv format?

The shapefile is a line format, so the Dissolve tool does not work (it requires a polygon input), as described in Getting list of distinct values from shapefile field using QGIS?

3

Go to DB Manager -> Virtual Layers -> QGIS layers, click on SQL Window button (or press F2), and write the next SQL expression:

SELECT DISTINCT your_field FROM your_layer ORDER BY your_field;

Once you get the result table, click on Load as new layer, uncheck Geometry column, and click on Load now!.

enter image description here

Now you have a table layer in QGIS, which you can export with right click -> Save As... to a CSV file, for example.

  • @ German Carrillo Thank you. Following your advice, I use this SQL expression: SELECT DISTINCT junk FROM 2015_08_01 ORDER BY junk; This error results: Query execution error on CREATE TEMP VIEW _tview AS SELECT DISTINCT junk FROM 2015_08_01 ORDER BY junk;: 1 - unrecognized token: "2015_08_01" FYI, 2015_08_01 is the shapefile name and junk is the string attribute field. What am I doing wrong? – Stu Smith Sep 29 '16 at 18:16
  • Your table name seems to be special (only numbers and underscores), so you need to use quotation marks. Try with "2015_08_01" in the SQL sentence. – Germán Carrillo Sep 29 '16 at 18:44
  • Note that there is also a button called "Add VIrtual Layer" in QGIS. You could use it to avoid opening the DB Manager. – Germán Carrillo Sep 29 '16 at 18:46

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.