CODEWITHSUNDEEP
sqlpostgresql
Kalifornium
Kalifornium

Reputation: 1072

Create a column composed of several columns in a postgres data table

I want to create a column in a table in postgres for special needs, this column must consist for example of a concatenation of two another column.

for example i have

LAYER: 'accessory'
TYPE: 'copper'

I want a column (symbology) to be filled automatically during an insertion or an update by

SYMBOLOGY: 'accessory - copper'

do I need a trigger to do this or is there some other ways to avoid the trigger.

Illustration

LAYER TYPE SYMBOLOGY
accessory copper accessory - copper

cordially

Upvotes: 1

Views: 129

Answers (1)

Schwern
Schwern

Reputation: 164679

You can use a generated column.

alter table things
  add column symbology text
  generated always as (layer || ' - ' || type)
  stored;

Or, if its only for some specific circumstances, you can create a view

create view thing_symbols as
select
  *,
  (layer || ' - ' || type) as symbology
from things;

Upvotes: 1

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