我的SQL UNION +極限

Question

這是我的查詢

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' 

這裏我的問題是我需要從每個SELECT語句只獲取一行。是否有可能通過「限制」來獲取它。請幫助

Answer 1

根據MySQL的網站，你可以申請限制個人選擇這樣的

(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