Mysql Nested Select

Mysql Nested Select is a SELECT query that is nested within a Select, Update, Insert or Delete SQL query.

Understand with Example:

The Tutorial illustrate an example from 'MySQL Nested Select'. To understand and elaborate example we create a table 'MyTable' that has the required fieldnames and datatypes respectively.

Query for creating table:

mysql> CREATE TABLE MyTable (
    ->              Empid int(10),
    ->              Empname varchar(60)
    ->              Salary int(90)
    ->            );
Query OK, 0 rows affected (0.13 sec)

Query for inserting data in table:

The Query insert into adds the records to the table 'MyTable'.

mysql>   insert into MyTable values(01,'Girish','20000');
Query OK, 1 row affected (0.02 sec)

mysql>     insert into MyTable values(02,'A','21000');
Query OK, 1 row affected (0.01 sec)

mysql>     insert into MyTable values(03,'C','22000');
Query OK, 1 row affected (0.00 sec)

mysql>     insert into MyTable values(04,'V','23000');
Query OK, 1 row affected (0.00 sec)

mysql>     insert into MyTable values(05,'B','24000');
Query OK, 1 row affected (0.00 sec)

mysql>     insert into MyTable values(06,'E','25000');
Query OK, 1 row affected (0.00 sec)

mysql>     insert into MyTable values(07,'Q','26000');
Query OK, 1 row affected (0.01 sec)

mysql>     insert into MyTable values(08,'W','27000');
Query OK, 1 row affected (0.01 sec)

mysql>     insert into MyTable values(09,'AS','28000');
Query OK, 1 row affected (0.00 sec)`

Query to view data inserted in table:

The Query is used to return the detail of the records from table 'mytable'.

mysql> select * from mytable;
+-------+---------+--------+
| Empid | Empname | Salary |
+-------+---------+--------+
| 1     | Girish  | 20000  |
| 2     | A       | 21000  |
| 3     | C       | 22000  |
| 4     | V       | 23000  |
| 5     | B       | 24000  |
| 6     | E       | 25000  |
| 7     | Q       | 26000  |
| 8     | W       | 27000  |
| 9     | AS      | 28000  |
+-------+---------+--------+
9 rows in set (0.01 sec)

Query for creating table name Employee:

We create another table 'Employee' that has the required fieldnames and datatypes respectively.

mysql> CREATE TABLE Employee(
    ->              Empid int(10),
    ->              Empname varchar(60),
    ->              Salary int(90),
    ->              DOB date
    ->            );
Query OK, 0 rows affected (0.01 sec)

Query for insertion of data in table:

The Query insert into adds the records or rows to the table 'Employee'.

mysql>     INSERT INTO Employee (Empid,Empname,Salary,DOB) VALUES
    ->     (01,'Habib',2014,20041202),
    ->     (02,'Karan',4021,20030411),
    ->     (03,'Samia', 22,20080223),
    ->     (04,'Hui Ling', 25,20081015),
    ->     (05,'Yumie', 29,19990126);
Query OK, 5 rows affected (0.00 sec)
Records: 5  Duplicates: 0  Warnings: 0

Query to view data inserted in table:

mysql> select * from employee;

Output:

+-------+----------+--------+------------+
| Empid | Empname  | Salary | DOB        |
+-------+----------+--------+------------+
|     1 | Habib    |   2014 | 2004-12-02 |
|     2 | Karan    |   4021 | 2003-04-11 |
|     3 | Samia    |     22 | 2008-02-23 |
|     4 | Hui Ling |     25 | 2008-10-15 |
|     5 | Yumie    |     29 | 1999-01-26 |
+-------+----------+--------+------------+
5 rows in set (0.00 sec)

Query for Mysql nested select:

The Nested Query is used to return those records from 'mytable' which are nested select query of table employee in the Where Clause.

mysql> SELECT * FROM mytable WHERE Empid in(SELECT Empid FROM  employee);

Output:-

+-------+---------+--------+
| Empid | Empname | Salary |
+-------+---------+--------+
| 1     | Girish  |  20000 |
| 2     | A       |  21000 |
| 3     | C       |  22000 |
| 4     | V       |  23000 |
| 5     | B       |  24000 |
+-------+---------+--------+
5 rows in set (0.00 sec)

Mysql Nested Select

Mysql Nested Select

Mysql Nested Select

Tutorials