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mysql 联合

不能,只能依次查询, 首先用条件查出来oracle的结果,然后再去查找mysql, (先查mysql,再查Oracle一样,看你自己需要)

如果是对多个列增加 UNIQUE 约束,通过 ADD UNIQUE KEY 处理。 mysql> CREATE TABLE test_unique( -> id INT, -> name VARCHAR(10), -> value VARCHAR(10) -> ); Query OK, 0 rows affected (0.08 sec) mysql> ALTER TABLE test_unique -> ADD U...

一使用SELECT子句进行多表查询 SELECT 字段名 FROM 表1,表2 … WHERE 表1.字段 = 表2.字段 AND 其它查询条件 SELECT a.id,a.name,a.address,a.date,b.math,b.english,b.chinese FROM tb_demo065_tel AS b,tb_demo065 AS a WHERE a.id=b.id 注:在...

SELECT m.user_id, b_total, c_total, d_total FROM a m, (SELECT user_id, COUNT(*) b_total FROM b GROUP BY user_id) n, (SELECT user_id, COUNT(*) c_total FROM c GROUP BY user_id) j, (SELECT user_id, COUNT(*) d_total FROM d GROUP BY...

CREATE TABLE `test` ('aaa' varchar(16) NOT NULL default '', 'bbb' varchar(16) NOT NULL default '', 'ccc' int(11) UNSIGNED NOT NULL default 0, KEY `sindex` (`aaa`,`bbb`,`ccc`) ) ENGINE=MyISAM COMMENT=''; 这样就在 aaa、bbb、ccc 3...

SELECT A.ID, A.NUMBER, A.PRICE, A.ORDER_TIME, B.USER_ID, B.STARTIME, B.STOPTIME, C.CHANNEL_PAY, D.COMPANY FROM D表 D LEFT JOIN A表 A ON A.COMPANY_ID = D.UID LEFT JOIN B表 B ON B.COMPANY_ID = D.UID LEFT JOIN C表 C ON C.COMPANY_I...

SELECT shop.id,shop.`name`,card.id as cid,card.sid,card.cname FROM shop , card WHERE shop.id = card.sid 这是一种最直白的方式查询方式,也可以用join

select a.name from A a,B b where a.department=b.department and b.leader="";

$sql ="select c.goods_name from c left join b on b.goods_id=c.goods_id left join a on a.goods_id=c.goods_id where a.isbest=0 and b.cat_id="B"";

表的连接查询,这个比较详细:http://www.cnblogs.com/still-windows7/archive/2012/10/22/2734613.html

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