pgdb=# UPDATE foo SET foo_name = '\\' WHERE foo_id = 100001; WARNING: nonstandard use of \\ in a string literal HINT: Use the escape string syntax for backslashes, e.g., E'\\'. pgdb=# UPDATE foo SET foo_name = '\r\n' WHERE foo_id = 100001; WARNING: nonstandard use of \\ in a string literal HINT: Use the escape string syntax for escapes, e.g., E'\r\n'.