concatenate two database columns into one resultset column

Question

I use the following SQL to concatenate several database columns from one table into one column in the result set:

SELECT (field1 + \'\' + field2 + \'\' + field

Answer 1

The SQL standard way of doing this would be:

SELECT COALESCE(field1, '') || COALESCE(field2, '') || COALESCE(field3, '') FROM table1

Example:

INSERT INTO table1 VALUES ('hello', null, 'world');
SELECT COALESCE(field1, '') || COALESCE(field2, '') || COALESCE(field3, '') FROM table1;

helloworld