MySQL Nested 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.
The create table statement is used to create a table 'MyTable' with 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 insert into keyword is used to add the records or values to the corresponding columns in a 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:
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 which has the required fieldnames and datatypes respectively specified in the below query.
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 is used to add 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 select Query is used to return the empid values from table employee. Based on the empid condition specified in Where Clause ,the select query returns you the records details from table 'mytable'.
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) |