执行嵌套更新，遇到错误You can't specify target table 'scar' for update in FROM clause
update scar
set main_resource_id=(
select id from scar2
where 1=1 and scar2.subject_templates_activity_resource_id=(
select main_resource_id from star
where 1=1 and star.id=scar.subject_templates_activity_resource_id
)
)
where 1=1
and scar.group_type=2
查询发现mysql不支持嵌套更新，只好改用表连接来进行更新
update scar
inner join scar2
inner join star
set scar.main_resource_id=scar2.id
where 1=1
and scar2.subject_templates_activity_resource_id=star.main_resource_id
and star.id=scar.subject_templates_activity_resource_id
and scar.group_type=2
and scar.activity_id in (select id from rsc_subject_cases_activity sca where sca.subject_cases_id='1')
感觉这样性能会查一些，不过等后续修改的时候再查执行计划看看