MySQL Nested Select Example

MySQL Nested Select is select query, that is nested inside the select, update and delete query based on the condition specified in a Where Clause. The Nested Select returns you the set of records from table based on the condition of nested select query specified in Where Clause.

Understand with Example

The Tutorial illustrate an example from 'MySQL Nested Select'. To understand the example we create a table 'MyTable' with given fieldnames and datatypes specified in the below example.

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 insert into adds the records or rows value to corresponding columns in 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 select will return the set of 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' with the required fieldnames and datatypes respectively as given below.

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 you the records value to the '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 select query returns you the Empid from table 'employee'. Further the select query returns you the records from 'mytable' based on the emp id specified in 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 Example

MySQL Nested Select Example

MySQL Nested Select Example

Tutorials