你可以试着这样做：

SELECT ...
FROM (
    SELECT f1,f2,f3 FROM table1
    UNION
    SELECT f1,f2,f3 FROM table2
)
WHERE ...

UNION ALL运算符可能就是您要找的。

使用此运算符，您可以将多个查询的结果集连接在一起，保留每个查询的所有行。请注意，UNION运算符(不带ALL关键字)将消除结果集中存在的任何“重复”行。UNION ALL操作符保留每个查询的所有行(并且可能执行得更好，因为它没有执行重复检查和删除操作的开销)。

在每个查询中，列数和每列的数据类型必须匹配。如果其中一个查询的列比另一个多，我们有时会在另一个查询中包含伪表达式，以使列和数据类型“匹配”。通常，在每个返回文字的查询的选择列表中包含一个表达式(一个额外的列)会很有帮助，以揭示哪些查询是该行的“源”。

SELECT 'q1' AS source, a, b, c, d FROM t1 WHERE ...
UNION ALL
SELECT 'q2', t2.fee, t2.fi, t2.fo, 'fum' FROM t2 JOIN t3 ON ...
UNION ALL
SELECT 'q3', '1', '2', buckle, my_shoe FROM t4

您可以将这样的查询放在一组括号中，并将其用作内联视图(或者MySQL行话中的“派生表”)，这样您就可以对所有行执行聚合操作。

SELECT t.a
     , SUM(t.b)
     , AVG(t.c)
  FROM (
         SELECT 'q1' AS source, a, b, c, d FROM t1
          UNION ALL
         SELECT 'q2', t2.fee, t2.fi, t2.fo, 'fum' FROM t2
       ) t
 GROUP BY t.a
 ORDER BY t.a

你可以试试这个记号：

SELECT * from table1,table2

一个更复杂的问题：

SELECT table1.field1,table1.field2, table2.field3,table2.field8 from table1,table2 where table1.field2 = something and table2.field3 = somethingelse

这类查询通常称为“隐式联接”，Explicit vs implicit SQL joins询问两者如何比较。在某些情况下，隐式查询执行计划与显式联接相同。

如果您的问题是这样的--选择ename、DNAME from emp、Department，而不使用联接..

然后，我会做这个..。

SELECT ename, (SELECT dname 
FROM dept
WHERE dept.deptno=emp.deptno)dname
FROM EMP

产出：

ENAME      DNAME
---------- --------------
SMITH      RESEARCH
ALLEN      SALES
WARD       SALES
JONES      RESEARCH
MARTIN     SALES
BLAKE      SALES
CLARK      ACCOUNTING
SCOTT      RESEARCH
KING       ACCOUNTING
TURNER     SALES
ADAMS      RESEARCH

ENAME      DNAME
---------- --------------
JAMES      SALES
FORD       RESEARCH
MILLER     ACCOUNTING

14 rows selected.

You should try this

SELECT t1.*,t2.* FROM t1,t2

SELECT * from table1 UNION SELECT * FROM table2

Union will fetch data by row not column,So If your are like me who is looking for fetching column data from two different table with no relation and without join.
In my case I am fetching state name and country name by id. Instead of writing two query you can do this way.

select 
   (
   select s.state_name from state s where s.state_id=3
   ) statename,
   (
   select c.description from country c where c.id=5
   ) countryname
   from dual;

where dual is a dummy table with single column--anything just require table to view

select 'test', (select name from employee where id=1) as name, (select name from address where id=2) as address ;

In this case we are assuming that we have two tables: SMPPMsgLogand SMSService with common column serviceid:

SELECT sp.SMS,ss.CMD 
FROM vas.SMPPMsgLog AS sp,vas.SMSService AS ss 
WHERE sp.serviceid=5431 
AND ss.ServiceID = 5431 
AND Receiver ="232700000" 
AND date(TimeStamp) <='2013-08-07' 
AND date(TimeStamp) >='2013-08-06' \G;

you can try this works always for me

query="SELECT * from tableX,tableY,table8";