QGIS Quick Tip - Python, SQL and Virtual Layers

In this episode I use a small Python script to get a attribute list from a selected field, and from only selected features.
Then I use Virtual Layers and a SQL command to create a single multi-polygon layer for those selected features.

[pythonGIS]

A heartfelt thank you for sharing! Your videos are absolutely fantastic!

[MOTTALUIZTUBE]

Hi Klas,

We can use the 'Speedy Layer' plugin for create the layer for use in SQL editor.

With that plugin we can create a memory layer with the selects features, this is a option of plugin, and use in SQL editor directly, not needing use the Python console and filter in SQL

[ВинсНуар-гб]

Dear Klas!
Thanks you for a lesson.
But i have one problem. When i trying to unite few polygons with 1 atribute i see next error:
"layer is not valid"
i use qgis 2.18.14 with windows 7
What could be the reason?

[courtney_geographic]

I selected a subset of line features that intersect with a polygon layer. Is it possible to modify the SQL query to list/group the selected line features by the polygon that they intersect with? For example, a result that lists: Polygon1 has line1, line2, line5. Polygon2 has line3, line4. As always, thanks for the video, it makes learning QGIS much more approachable.