SQL Update

SQL Update is used to modify the existing structure of table. The modification includes setting a new column records values on the basis of condition specified in Where Clause.

SQL Update

SQL Update

     

SQL Update is used to modify the existing structure of table. The modification includes setting a new column records values on the basis of condition specified in Where Clause.

Understand with Example

The Tutorial illustrate an example from 'SQL Update'. To understand the example we create a table 'Employee' with the required field name and datatype respectively.

 

 

Query for creating table name Employee:

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 Multiple insertion of data in table:

The insert into keyword is used to add the values 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 multiple updating data inserted in table:

The below Query is used to update the table 'employee' by setting a new values for each employee name based on the condition specified in Where Clause.

mysql> update employee set empname='A'where empid=1;
Query OK, 0 rows affected (0.00 sec)
Rows matched: 1  Changed: 0  Warnings: 0
mysql>  update employee set empname='b'where empid=2;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0
mysql>  update employee set empname='c'where empid=3;
Query OK, 1 row affected (0.02 sec)
Rows matched: 1  Changed: 1  Warnings: 0
mysql>  update employee set empname='d'where empid=4;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0
mysql>  update employee set empname='e'where empid=5;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

Output:-

mysql> select * from employee;
+-------+---------+--------+------------+
| Empid | Empname | Salary | DOB        |
+-------+---------+--------+------------+
| 1     | A       | 2014   | 2004-12-02 |
| 2     | b       | 4021   | 2003-04-11 |
| 3     | c       | 22     | 2008-02-23 |
| 4     | d       | 25     | 2008-10-15 |
| 5     | e       | 29     | 1999-01-26 |
+-------+---------+--------+------------+
5 rows in set (0.00 sec)