I got the answer, thanks.

I have two tables:
tb1:
ID USERNAME
1 u11
2 u12
3 u13

tb2:
ID USERNAME
2 u12

I have two tables:

tb1:
Name Email Location
-----------------------------------
user1 email1 address1
user2 email2 address2
user3 email3 address3...

I have three tables, table1 store records which may have next level ID(child), table2 lists corresponding child ID, and table3 stores the possible message for that particular ID.

table1:...

I have two tables:

table1:
----------------------
id name member
----------------------
1 user1
2 user2
3 user3
table2:

still have problem.
For example:

mysql> select uname from authuser;
+--------+
| uname |
+--------+
| user1 |
| user12 |
| user2 |

I use hosting services, so it's impossible for me to upgrade it, I am just wondering if there a way to do it, except using sub-select statement.

I use Mysql 3.23 server, I think it doesn't support sub-select statement, is there alternative to do that? thanks.

In database I have three tables: t1,t2,t3
all three tables contain the same field (username)
t1(username)
-------
user1
user2
user3
user4
user5

I have three tables.

table1:
|-------|-----------|
| Name | Studyarea |
|------|-----------|
| Joe | 1 |
| Joe | 2 |
| Chris | 1 |
| Mike | 3 |

I would like to know how I can backup Mysql tables from hosting server to my local pc? I don't want to use phpMyAdmin, is there some simple commands to do that(I use PHP)? and how to restore it back...