A.select * from ds.phones where Brand="華為"and model="P20"
B.select * from ds.phones where Brand="華為"or model="P20"
C.select * from ds.phones where having"華為"and"P20"
D.select * from ds.phones where having"華為"or"P20"
A.where
B.group by
C.order by
D.limit