If you don't have the admin access to the server, then use the below query:
ALTER ROLE <your_login_role> SET search_path TO a,b,c;
Two important things to keep in mind are as follows
- If the schema name is not simple, then it should be wrapped in double-quotes.
- The order in which you set default schemas a, b, c matters, as it is also the order in which the schemas will be looked up for tables.
Therefore, if you have the same table name in more than one schema among the defaults, then there will be no ambiguity, the server will always use the table from the first schema as you have specified for your search_path.