How to remove group and project in Gerrit ?

Group
1. access gerrit sql database
   cmd: ssh -p 29418 150.236.40.165 gerrit gsql
2. gerrit> delete from ACCOUNT_GROUP_NAMES where name='group name';
3. gerrit> delete from ACCOUNT_GROUPS where name='group name';

Project
1. access gerrit sql database
   cmd: ssh -p 29418 150.236.40.165 gerrit gsql
2. gerrit> delete from projects where name=<project name>;
3. gerrit> delete from ref_rights where project_name=<project name>;
4. go to folder /gerrit/review_site/git, remove <project name>.git

Example for remove project:
Step 1:
ecdshawk@mtvserver2:/project/ecds/gerrit/review_site/db>ssh -p 29418 150.236.40.165 gerrit gsql
Welcome to Gerrit Code Review 2.1.6.1
(H2 1.2.134 (2010-04-23))
 
Type '\h' for help.  Type '\r' to clear the buffer.
 
gerrit>
 
Step 2:
gerrit> delete from projects where name='rmproject';
UPDATE 1; 1 ms
 
Step 3:
gerrit> delete from ref_rights where project_name='rmproject';
UPDATE 1; 1 ms

Step 4:
ecdshawk@mtvserver2:/project/ecds/gerrit/review_site/git>ls
fproject.git  rmproject.git
ecdshawk@mtvserver2:/project/ecds/gerrit/review_site/git>rm -rf rmproject.git/
ecdshawk@mtvserver2:/project/ecds/gerrit/review_site/git>ls
fproject.git

Note: The projects is removed from database with Gerrit version 2.2. The method is simply. Delete project folder from Gerrit repo folder directly and restart Gerrit service.