Postgres Error: More than one row returned by a subquery used as an expression

Question

I have two separate databases. I am trying to update a column in one database to the values of a column from the other database:

UPDATE customer
SET customer         


        

Answer 1

USE LIMIT 1 - so It will return only 1 row. Example

customerId- (select id from enumeration where enumerations.name = 'Ready To Invoice' limit 1)