mysql使用md5列连接4个表

I have four big tables in mysql connected with the md5 string as below

main table has the md5 string as the primary key say

table1-|md5_col1|col2|....
table2-|same_md5_frm_table1|col2|col3|....
table3-|same_md5_frm_table1|col2|col3|....
table4-|same_md5_frm_table1|col2|col3|....

when I make join (inner or left or right) the mysql service is getting stopped.

I have made a view making all the columns joined together and when fetch from view the mysql service is getting stopped.

Even when I select very less columns the mysql service is getting stopped.

Tried many way but no result..

Can any one help me how to get the result from all the four tables?

Thanks in advance