MySql queries for update and delete operations

               Update is a SQL operation which updates a column or one or more column.

Let us create the query.The syntax is given below.

Syntax:

‘UPDATE tablename set value1,valu2,…,valuen where condition;’

Query: single field update

mysql> UPDATE Students SET age=15 WHERE name = 'Edward';

Query OK, 1 row affected (0.054 sec)

Rows matched: 1  Changed: 1  Warnings: 0

Display the table contents by SELECT Query:

mysql> SELECT * FROM students;

+----+--------+------+

| id | name   | age  |

+----+--------+------+

|  1 | ajay   |   12 |

|  2 | bob    |   15 |

|  3 | Edward |   15 |

|  4 | Jey    |   13 |

+----+--------+------+

4 rows in set (0.009 sec)

Update query : Multiple field update

mysql> UPDATE Students SET name='John',age=12 WHERE id =3;

Query OK, 1 row affected (0.072 sec)

Rows matched: 1  Changed: 1  Warnings: 0

Display the result.

mysql> SELECT * FROM Students;

+----+------+------+

| id | name | age  |

+----+------+------+

|  1 | ajay |   12 |

|  2 | bob  |   15 |

|  3 | John |   12 |

|  4 | Jey  |   13 |

+----+------+------+

4 rows in set (0.007 sec)

Delete query:

Deletion is the process of removing data or tuple.

Syntax:

‘DELETE FROM tablename where condition;’

Eg:

mysql> DELETE FROM Students where id = 2;

Query OK, 1 row affected (0.069 sec)

Display  the output as follows.

mysql> SELECT * FROM Students;

+----+------+------+

| id | name | age  |

+----+------+------+

|  1 | ajay |   12 |

|  3 | John |   12 |

|  4 | Jey  |   13 |

+----+------+------+

3 rows in set (0.007 sec)

This is the way of creating delete and update queries in mysql. Hope, this code is useful to you!!!