MySQL update multiple tables (replication)

Source: Internet
Author: User
Tags mysql update

We have two tables, one for the product table, one for the products, the price for the product, and one for the Productprice table, which we want to update the Price field in the Productprice table to 80% of the price field in the prices table.
In MySQL we have several means to do this, one is update table1 t1, table2 ts ... The way:

Copy CodeThe code is as follows:
UPDATE product P, Productprice pp
SET pp.price = Pp.price * 0.8
WHERE P.productid = Pp.productid
and p.datecreated < ' 2004-01-01 '


Another way is to use inner join and then update:

Copy CodeThe code is as follows:
UPDATE Product P
INNER JOIN Productprice pp
On p.productid = Pp.productid
SET pp.price = Pp.price * 0.8
WHERE p.datecreated < ' 2004-01-01 '


Alternatively, we can use the left outer join to do a multi-table update, for example, if there is no product price record in the Productprice table, set the IsDeleted field of the product table to 1, the following SQL statement:

Copy CodeThe code is as follows:
UPDATE Product P
Left JOIN Productprice pp
On p.productid = Pp.productid
SET p.deleted = 1
WHERE Pp.productid is null


In addition, the above examples are related to the two tables, but only update the records in a table, in fact, you can update both tables, the following SQL:

Copy CodeThe code is as follows:
UPDATE Product P
INNER JOIN Productprice pp
On p.productid = Pp.productid
SET pp.price = Pp.price * 0.8,
P.dateupdate = Curdate ()
WHERE p.datecreated < ' 2004-01-01 '


Two tables are associated, updating the Price field of the Productprice table and the Dateupdate two fields of the Product table field.

MySQL update multiple tables (replication)

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