MySQL联合+限制

Question

这是我的查询

select PhoneNumber as _data,PhoneType as _type from contact_phonenumbers where ContactID = 3 and Type = 'R' and PT = 'M' 
union 
SELECT EmailID,Type  from contact_emails where ContactID = 3 and Type = 'P' 
UNION
SELECT EmailID,Type from contact_emails where ContactID = 3 and Type = 'O' 

我的问题是我只需要从每个选择语句中获取一行。是否可以通过“limit”获取。

Answer 1

根据 MySQL 网站，您可以像那样对单个选择应用限制

(SELECT a FROM t1 WHERE a=10 AND B=1 ORDER BY a LIMIT 10)
UNION
(SELECT a FROM t2 WHERE a=11 AND B=2 ORDER BY a LIMIT 10);

http://dev.mysql.com/doc/refman/5.0/en/union.html