MySQL:如何在WHERE子句中批量选择具有多对的行

Question

假设我有一张桌子,email_phone_notes看起来像这样:

+-----------------------+--------------+------+-----+---------+-------+
| Field                 | Type         | Null | Key | Default | Extra |
+-----------------------+--------------+------+-----+---------+-------+
| email                 | varchar      | NO   | PRI | NULL    |       |
| phone                 | varchar      | NO   | PRI | NULL    |       |
| notes                 | text         | NO   |     | 0       |       |
+-----------------------+--------------+------+-----+---------+-------+

因此,每个电子邮件/电话组合都是唯一的,但您可以拥有多个电话号码不同的电子邮件地址,反之亦然.这有点做作,但它反映了我的情景.

我想做这样的查询:

SELECT * FROM email_phone_notes  WHERE email = 'foo@bar.com' AND phone = '555-1212';

但是,我想一次做多对,所以我不必进行多次SELECT查询.将对子组合在一起也很重要,因为我不想返回未请求的错误电话/电子邮件组合.

我可以做这样的事情,但是对于数百个值的可能性,查询将非常长.

SELECT * FROM email_phone_notes WHERE ( 
  (email='foo@bar.com' && phone='555-1212') || 
  (email='test@test.com' && phone='888-1212') || 
   ...

有更优雅的解决方案,还是我应该坚持这个？谢谢!

Answer 1

如果您使用优雅的SQL,则可以使用行构造函数:

SELECT * FROM email_phone_notes WHERE (email, phone) IN (
  ('foo@bar.com'  , '555-1212'),
  ('test@test.com', '888-1212')
  -- etc.
);

但是,这根本不是索引友好的,不会推荐给任何大小的表.相反,您可以使用所需的对实现表,并将其与表连接:

SELECT * FROM email_phone_notes NATURAL JOIN (
  SELECT 'foo@bar.com' AS email, '555-1212' AS phone
UNION ALL
  SELECT 'test@test.com', '888-1212'
-- etc.
) t;

或者预填充(临时)表:

CREATE TEMPORARY TABLE foo (PRIMARY KEY (email, phone)) Engine=MEMORY
  SELECT email, phone FROM email_phone_notes WHERE FALSE
;

INSERT INTO foo
  (email, phone)
VALUES
  ('foo@bar.com'  , '555-1212'),
  ('test@test.com', '888-1212')
  -- etc.
;

SELECT * FROM email_phone_notes NATURAL JOIN foo;