MYSQL将数据从一个表转移到另一个表的过程

Question

I'm new in mysql and plsql as well. I was trying to write one procedure to transfer data from one table to another but couldnt reach to end.

I have one table Mall_Sales (Consist of three different malls like Delhi_Mall, Mumbai_Mall, Chennai_Mall and these malls falls in column Mall with their period of transaction in column name Period )

Mall_Sales

Mall              Period
Delhi_Mall        2015-09-01
Delhi_Mall        2015-09-02
Delhi_Mall        2015-09-03
Mumbai_Mall       2015-09-01
Mumbai_Mall       2015-09-02
Chennai_Mall      2015-09-01
Chennai_Mall      2015-09-02

And

Latest_Period_Mall
Mall              Period
Delhi_Mall        2015-09-03
Mumbai_Mall       2015-09-02
Chennai_Mall      2015-09-02

I'm trying to write a procedure whenever period of mall updates in Mall_Sales, Store MAX period of all malls in Latest_Period_Mall table.

And whenever new MAX date comes from Mall_Sales table should replace the existing records in Latest_Period_Mall table.

I have tried this

Create or replace Procedure Update_Data
AS
    INSERT into Latest_Period_Mall table(Mall, Period)
        Select Mall, MAX(Period) Period 
        from Mall_Sales
        group by Mall
Go

Please correct me with your inputs and the every time updation part in Latest_Period_Mall table rather than adding records.

Best

Answer 1

A view essentially saves the query:

create view Latest_Period_Mall as 

    Select Mall, MAX(Period) Period 
    from Mall_Sales
    group by Mall

So that you can simply query the view like a regular table.

    select * from latest_period_mall