How to insert content of multiple columns into a new column in sql?

Question

I want to combine the content of two columns and insert it into a new column.

But it does not work. Example:

create table car(
   id bigint NOT NULL,
   manufacture character varying(255),
   number character varying(255),
   result character varying(255)
)

insert into car (result)
select concat(manufacture, ' ', number) from car

Result:

ERROR:  NULL-Value in column „id“ error Not-Null-Constraint
DETAIL:  Failed line contains (null, null, null, bmw 123).

How can I just update the specific row, and leave all other values as it is?

I think you actually mean to "update" rather than "insert". Update changes something about an existing row. Insert adds a new row. (assuming you want 1, bmw, 123, bmw 123) — Lefty
– Lefty, Commented Dec 2, 2014 at 10:56
What's your plan for situations where the number of characters in the manufacturer and number fields is more than 255? — Dan Bracuk
– Dan Bracuk, Commented Dec 2, 2014 at 10:56

Paul Connolly · Accepted Answer · 2014-12-02 10:54:22Z

3

update car set result = concat(manufacture, ' ', number)

answered Dec 2, 2014 at 10:54

Paul Connolly

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