Deleting features with identical table attributes in QGIS

Question

How do I delete features with identical table attributes in QGIS? Otherwise, is there a tool like the 'Delete Identical Tool' in ArcGIS?

For example, if I had 4 rows, and 3 columns, where I wanted to delete identical features based on 2 columns:

id	value 1	value 2
1	A	m
2	A	m
3	A	p
4	B	m

I want it to be reduced to only 1 feature for each identical set of attributes:

id	value 1	value 2
1	A	m
3	A	p
4	B	m

In ArcGIS Desktop, this is a simple tool shown below called 'Delete Identical', where I can select one or more columns at the same time. I use this tool all the time, am switching to QGIS.

Answer 1

For future reference: the next version of QGIS (3.6) includes a built-in 'Delete duplicates by attribute' tool which does exactly this.

Answer 2

In QGIS 3, you could use 'Add autoincremental field' tool to distinguish the identical set of attribute fields.

If your ABC field holds A, B, ... and mnp field holds m, p, ... like below image;

Select these ABC, mnp fields in the Group values by option, and keep other options at the default setting.

This tool will return a new Incremental layer. You will see AUTO field with 0 and 1. (You may have 2 or bigger numbers if you have many duplicated records).

Select and highlight AUTO= 0 and go to Save As, using only selected features option.

Answer 3

There is a possibility of using a 'Virtual Layer' through Layer > Add Layer > Add/Edit Virtual Layer...

Let's assume there is a point layer 'testpoints' with identical table attributes, see image below.

With the following query, it is possible to delete features with identical table attributes.

SELECT "id", "value1", "value2", geometry
FROM "testpoints"
GROUP BY "value1", "value2"

The output layer with its attribute table will look like

P.S. Mind that this solution does make sense if features possess the same geometry

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References:

• How do I (or can I) SELECT DISTINCT on multiple columns?