Hi,all friend:
I want to enjoy a experience about about creating vds
if you use the sql
create vds common_space.testUnionTable as select a.* from mysql.csp.admin_user a union all select b.* from mysql.csp.admin_user b
your vds can be created but you don’t to execute this vds like use this SQL:
select * from common_space.testUnionTable
the right sql rule is 
create vds common_space.testUnionVds3 as select u.* from (
select * from mysql.csp.admin_user union all select * from mysql.csp.admin_user ) u