Speaking SQL (part 1) - Old Data For New

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And finally, there's an UPDATE command designed to help you change existing values in a table; it looks like this:

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UPDATE <table_name> SET <field_name> = <new_value>

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The above command would act on all values in the field <field_name>, changing them all to <new_value>. If you'd like to alter the value in a single field only, you can use the WHERE clause, as with the DELETE command.

Using this information, I could update John Doe's email address in the table:

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mysql> UPDATE members SET email = 'john@somewhere.com' WHERE member_id = 1;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

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You can alter multiple fields by separating them with commas.

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mysql>  UPDATE members SET email = 'john@somewhere.com', lname = 'Doe The
First
WHERE member_id = 2;
Query OK, 1 row affected (0.05 sec)
Rows matched: 1  Changed: 1  Warnings: 0

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And your table will now look something like this:

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+-----------+-------+---------------+---------+--------------------------+
| member_id | fname | lname         | tel     | email                    |
+-----------+-------+---------------+---------+--------------------------+
|         1 | John  | Doe The First | 1234567 | john@somewhere.com       |
|         2 | Jane  | Doe           | 8373728 | jane@site.com            |
|         3 | Steve | Klingon       | 7449373 | steve@alien-race.com     |
|         4 | Santa | Claus         | 9999999 | santa@the-north-pole.com |
+-----------+-------+---------------+---------+--------------------------+
4 rows in set (0.00 sec)

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And that's about it for the first part of this article. Next time, I'll be showing you how to get your data out of the table with a variety of SELECT statements - so make sure you come back for that!

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