sqlite IFNULL() in postgres
try coalesce:
The COALESCE function returns the first of its arguments that is not null. Null is returned only if all arguments are null
SELECT coalesce(max(code_id) + 1, 1) FROM configentries WHERE configtable_id = ...
Try this, Select NULLIF(Max(code_id), 0) +1 from configentries WHERE configtable_id = ...
All answers are good, but wil only work in situations where only one row is returned.
If you want to query multiple rows and receive a default value if 0 Rows are found, you can use this:
SELECT example_field from "example_table" WHERE attribute='x'UNION SELECT 'my_default_value' FROM "example_table" WHERE (SELECT example_field from "example_table" WHERE attribute='x' LIMIT 1) is NULL