Adding text from one field to another in QGIS attribute table?

Question

I would like to copy names from field 'Uch_1' to 'Uchastok' but not all. Names in 'Uch_1' should be copied and replace only where in 'Uchastok' cells are 'NULL' but if not, it remains without changes.

Any ideas what code should I use in Field Calculator?

Answer 1

there are a few options

First

Select all cells with value 'NULL'

Open field calculator

• You will see the first option checked: 'only update xxx selected features'. Keep it checked!!
• check 'update existing field'
• select 'Uchastok'

In the expression panel add "Uch_1"

Press 'OK'

Second

• check 'update existing field'
• select 'Uchastok'

Add following code:

case

when "Uchastok" is null then "Uch_1"

else "Uchastok"

end