Can you combine multiple updates in one query?
You can combine an UPDATE with a CASE like this: The ELSE title is very important, otherwise you will overwrite the rest of the table with NULL. You might wonder why on earth you’d want to make multiple updates in a single query.
How to update multiple rows from results from select?
SELECT `o`.`Order_ID` FROM `Orders` `o` JOIN `CustomerDetails` `cd` ON `cd`.`Customer_ID` = `o`.`Customer_ID` WHERE `o`.`OrderPlaceServerTime` >= ‘2013-06-01 00:00:00’ AND `o`.`OrderPlaceServerTime` <= ‘2013-06-31 23:59:59’ AND `cd`.`SalesRep_ID` = 6
Why do I need to run multiple updates in MySQL?
Also, keep in mind that in order to gain advantage of MySQL optimizations all those UPDATE queries need to be run in a batch. Running each UPDATE query when the page is viewed for example is not the same thing (and that’s pretty much the problem I wanted to solve as efficiently as possible).
How do I update an order in MySQL?
UPDATE Orders o JOIN CustomerDetails d ON d.Customer_ID = o.Customer_ID SET o.SalesRep_ID = 6 WHERE o.OrderPlaceServerTime >= ‘2013-06-01 00:00:00’ AND o.OrderPlaceServerTime <= ‘2013-06-31 23:59:59’ AND d.SalesRep_ID = 6 There is a little trick to this. You have to fool MySQL into thinking that you are working on different tables.
Is it possible to perform multiple updates with a single update SQL?
But if you have hundreds or thousands or millions of mappings to perform, then you are likely to exceed the limits of the SQL statement length in your DBMS. Of course, this will cause a write on every record, and with indexes, it can be an issue, so you can filter out only the rows you want to change:
How to update multiple records in one query stack?
78,77 are the user Ids and for those user id I need to update the base_id 999 and 88 respectively.This works for me. Camille’s solution worked. Turned it into a basic PHP function, which writes up the SQL statement. Hope this helps someone else.
Which is better for multiple updates InnoDB or MyISAM?
As you can see the results are very interesting. You can clearly see the difference of both storage engine and transactions (at least for MyISAM). In other words, if you use MyISAM (and many people do), use transactions for multiple updates. If you use InnoDB switch to MyISAM and them use transactions.