Question

I hasn’t been writing any MySql stored procedures before, so I don’t know them at all. I have one database table which has some records in it. The main column is dateTime – when this record was saved in the database.

I have wrote the MySql stored procedure to select every record from the specified date:

CREATE PROCEDURE getMessages(IN dateFrom DATETIME)   
    SELECT * FROM EsbMessage WHERE dateTime <= dateFrom;

And this is the call:

CALL getMessages('2012-10-04 13:11:09');

This works correctly, it returns me the records from the specified date.

What I need to do is:

1. If the record is over one week old, I need to update the other
   column.
2. If the record is over one year old, I need to delete that record.

I can easily do this programmatically, but in this case I have to do this using stored procedure.

So I’am thinking of something like this:

CREATE PROCEDURE updateMessages(IN dateFrom DATETIME)   
    BEGIN
      SELECT * FROM EsbMessage WHERE dateTime <= dateFrom;
      #for each message
      #if the message is over one week old but not over one year old:
      UPDATE EsbMessage SET body = '';
      #if message is over one year old:
      DELETE FROM EsbMessage WHERE dateTime = #message.dateTime
END

But I don’t know how to use for loop in stored procedure, and how to write if statements depending on my requirements and the other thing I don’t now how to count the dates in MySql. For e.g. If I have the current date then I need to subtract the 365 days from the current date.

Could somebody help me with this issue?

Answer 1

How to loop and to use if clauses is described here: http://www.mysqltutorial.org/stored-procedures-loop.aspx

I would do it without loops:

CREATE PROCEDURE updateMessages(IN dateFrom DATETIME)   
BEGIN      
  UPDATE EsbMessage SET body = '' where dateTime <= dateFrom -(86400*7); //86400 = 1 day
  #if message is over one year old:
  DELETE FROM EsbMessage where dateTime <= dateFrom -(86400*365);
END