SQL关键字的执行顺序

select b.filed2 from tableA a left join tableB b on a.id = b.aid where a.filed2 = 'xxx' group by b.filed2 having sum(b.filed3) >  num order by b.filed2 asc limit num

① from 

② left join

③ on

④ where

⑤ group by

⑥ having 

⑦ select

⑧ order by

⑨ limit