To get username using ID from two tables, you need to use JOIN and join the tables.
Let us create a table −
Example
mysql> create table demo77 -> ( -> userid int not null primary key, -> username varchar(20) -> ); Query OK, 0 rows affected (2.63
Insert some records into the table with the help of insert command −
Example
mysql> insert into demo77 values(1,'John'); Query OK, 1 row affected (0.19 mysql> insert into demo77 values(2,'Bob'); Query OK, 1 row affected (0.36
Display records from the table using select statement −
Example
mysql> select *from demo77;
This will produce the following output −
Output
+--------+----------+
| userid | username |+--------+----------+
| 1 | John || 2 | Bob |
| 3 | Mike |+--------+----------+
Following is the query to create second table −
Example
mysql> create table demo78 -> ( -> id int not null primary key, -> countryname varchar(20), -> constraint fk_id foreign key(id) references demo77(userid) -> ); Query OK, 0 rows affected (0.75
Insert some records into the second table with the help of insert command −
Example
mysql> insert into demo78 values(1,'US'); Query OK, 1 row affected (0.14 mysql> insert into demo78 values(2,'AUS'); Query OK, 1 row affected (0.15
Display records from the second table using select statement −
Example
mysql> select *from demo78 -> ;
This will produce the following output −
Output
+----+-------------+
| id | countryname |+----+-------------+
| 1 | US || 2 | AUS |
+----+-------------+2 rows in set (0.00 sec)
Following is the query to get username by using id by joining both the tables −
Example
mysql> select username from demo77 -> join demo78 -> on demo77.userid=demo78.id;
This will produce the following output −
Output
+----------+
| username |+----------+
| John || Bob |
+----------+2 rows in set (0.05 sec)