Question

so here is my issue:

i have 3 tables:

• ROLE : RID ,NAME
• CLIENT : CID, NAME
• USER : UID, RID, CID, USERNAME, PASSWORD

Below is the SQL statement that I have written:

SELECT USER.UID,USERNAME,PASSWORD,ROLE.NAME, ROLE.RID 
FROM USER 
INNER JOIN ROLE ON USER.RID=ROLE.RID 
WHERE CID=1;

The above statement is returning only 1 row when there should actually be 2 rows.

I don’t understand what is not working.

When i do the following, i get my 2 rows:
SELECT *
FROM USER
WHERE CID =1;

Note that i am using spring framework and also implementing a RowMapper. Below is my actual code with the field names as per the dbase.

public List<User> viewUserClient(int client_id) {
    String sql =
            "SELECT USER.ID,USERNAME,PASSWORD,ACTIVE,ROLE.NAME, ROLE.ID FROM USER INNER JOIN ROLE ON USER.ROLE_ID=ROLE.ID WHERE CLIENT_ID=?";
    List<User> users = this.getJdbcTemplate().query(sql, new Object[] { client_id }, new UserClientRowMapper());
    return users;
}

private static final class UserClientRowMapper implements RowMapper<User> {
    public User mapRow(ResultSet rs, int rowNum) throws SQLException {
        User user = new User();
        Client client = new Client();
        Role role = new Role();

        user.setID(rs.getInt("ID"));
        user.setUSERNAME(rs.getString("USERNAME"));
        user.setPASSWORD(rs.getString("PASSWORD"));
        user.setACTIVE(rs.getBoolean("ACTIVE"));

        role.setNAME(rs.getString("NAME"));
        role.setID(rs.getInt("ROLE.ID"));

        client.setId(rs.getInt("id"));
        client.setName(rs.getString("name"));

        user.setRole(role);
        user.setClient(client);
        return user;
    }

}

Thanks in advance for your help.

Answer 1

The INNER JOIN keyword returns rows when there is at least one match in both tables. If there are rows in “USER” that do not have matches in “ROLE”, those rows will NOT be listed; of the two users returned by your plain select query, probably one has a null RID column value, or a value that is not in ROLE table.

Use a LEFT JOIN.