MySQL IN AND OR

Send to Kindle

MySQL IN??? MySQL OR??? MySQL AND???
When I use one and when I use other?

we will use the city table to this tutorial:

+-------------+----------+------+-----+---------+----------------+
| Field       | Type     | Null | Key | Default | Extra          |
+-------------+----------+------+-----+---------+----------------+
| ID          | int(11)  | NO   | PRI | NULL    | auto_increment |
| Name        | char(35) | NO   |     |         |                |
| CountryCode | char(3)  | NO   | MUL |         |                |
| District    | char(20) | NO   |     |         |                |
| Population  | int(11)  | NO   |     | 0       |                |
+-------------+----------+------+-----+---------+----------------+



Let’s see a simple rule to clarify this:

AND – we use AND to add a new condition which will need to be true:

SELECT * FROM City WHERE CountryCode = 'BRA' AND Population > 1000000 AND District LIKE 'São Paulo';

This query will return Cities which CountryCode is BRA and Population is bigger than 1000000 and Discrict is São Paulo, this three condition need to be true.

OR – we use OR to add a new condition which or one or other needs to be true:

SELECT * FROM City WHERE Population > 1000000 OR District LIKE 'São Paulo';

This query will return Cities which have a population bigger than 1000000 or have São Paulo as their district .
IN – we use in the same way which we use OR but for the same column:

SELECT * FROM City WHERE CountryCode = 'USA' OR CountryCode = 'BRA' OR CountryCode = 'IRL';
SELECT * FROM City WHERE CountryCode IN ('USA', 'BRA', 'IRL');

This both queries will return the same result, all cities which are in USA, BRA or IRL.

Send to Kindle
This entry was posted in Uncategorized. Bookmark the permalink.
  • http://hchost.blogspot.com Guilherme Mauro

    Valeu amigo, me tirou algumas dúvidas! =)