一道Oracle面试年薪70W的DBA题目
有表order_list数据如下
源数据:(order_list)
user food
Jack Hamburger
Jack Hamburger
Tom Hamburger
Tom SausageMark Hamburger
Mark Coke
查询之后数据:
user Hamburger Sausage Coke
Jack 2 0 0
Tom 1 1 0
Mark 1 0 1
源数据中food种类不确定,请写出您认为最高效的查询语句!
源数据:(order_list)
user food
Jack Hamburger
Jack Hamburger
Tom Hamburger
Tom SausageMark Hamburger
Mark Coke
查询之后数据:
user Hamburger Sausage Coke
Jack 2 0 0
Tom 1 1 0
Mark 1 0 1
源数据中food种类不确定,请写出您认为最高效的查询语句!