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/*DDL Information For - test.a1*/
---------------------------------
Table Create Table
------ --------------------------------------
a1 CREATE TABLE `a1` (
`str1` char(2) DEFAULT NULL
) ENGINE=MEMORY DEFAULT CHARSET=utf8
/*DDL Information For - test.a2*/
---------------------------------
Table Create Table
------ --------------------------------------
a2 CREATE TABLE `a2` (
`str1` char(2) DEFAULT NULL
) ENGINE=MEMORY DEFAULT CHARSET=utf8
select * from a1;
query result(2 records)
str1
aa
bb
select * from a2;
query result(2 records)
str1
cc
dd
select a1.str1,a2.str1 from a1,a2 order by a1.str1;
query result(4 records)
str1 str1
aa cc
aa dd
bb cc
bb dd
select a1.str1,a2.str1 from a2,a1 order by a1.str1;
query result(4 records)
str1 str1
aa cc
aa dd
bb cc
bb dd
这样结果就一样了。
select a1.`name`,a1,sex,a1,age,a2.address,a2.email from a1,a2;
select * from A1,A2,A3 where A1.field1 = '张三' or A2.field1 = '张三' or A3.field1 = '张三';
alter table A modify field4 char(20) first;
alter table A modify field1 char(2) after fieldN(最后一个字段);
create temporary table tmp select 字段2,字段3,...,字段N from 你的表名;
truncate table 你的表名;
insert into 你的表名(字段2,字段3,...,字段N) select * from tmp;