SQL-Like Inner Join on IDs in Two Layers in QGIS

Question

Using QGIS v2.6.0-Brighton.

This question is not about editing layers geographically in anyway. It is merely trying to find data from two layers as you would in an SQL Query and append an extra ID to the second layer.

I have one polyline layer each identified with two different IDs. There is a point layer also with one of these IDs, I wish to find this corresponding ID and append them as a column to the point layer.

How do I do this without finding each row individually and typing it in manually (i.e. larger scale)? I would prefer to use SQL like syntax but if there is a GUI as well that would be ideal. Happy to install official plugins.

Answer 1

Found the solution. Albeit without SQL style joining, but this structure operates in the same way and is clearer so it is preferable.

1. Double click on the layer you wish to join extra attributes to;
2. Click on 'Joins' on the left;
3. Click the '+' symbol at the bottom to add a new join to the double clicked layer;
4. Select the join layer (layer you wish to take attributes from), the join field to which will be used to join to the target field from the target layer (the one in which you are in the properties window);
5. Choose which fields are added to avoid overpopulating your table;
6. Press OK in the vector join window to accept this join; and
7. Press OK/Apply to execute the join and this should now be visible in the attribute table.

A link to a tutorial can be found here