Mysql multi-Table update SQL statement Summary

Mysql multi-Table update SQL statement summary mysql multi-Table update has several different writing methods. Www.2cto.com suppose we have two tables. One Table stores Product information for the Product table, with the Product Price column Price. The other table is the ProductPrice table, update the Price field in the ProductPrice table to 80% of the Price field in the Price table. In Mysql, we have several ways to do this. One is update table1 t1, table2 ts... method: www.2cto.com UPDATE product p, productPrice ppSET pp. price = pp. price * 0.8 WHERE p. productId = pp. productIdAND p. dateCreated <'2014-01-01 'another method is to use inner join and then UPDATE: UPDATE product pINNER JOIN productPrice ppON p. productId = pp. productIdSET pp. price = pp. price * 0.8 WHERE p. dateCreated <'2014-01-01 'In addition, we can also use left outer join to update multiple tables. For example, if If there is no Product price record in the roductPrice table, set the isDeleted field of the product table to 1. The following SQL statement: www.2cto.com UPDATE Product pLEFT JOIN productPrice ppON p. productId = pp. productIdSET p. deleted = 1 WHERE pp. productId IS null. In addition, in the above examples, two tables are associated, but only the records in one table can be updated at the same time, as shown in the following SQL: UPDATE product pINNER JOIN productPrice ppON p. productId = pp. productIdSET pp. price = pp. price * 0.8, p. dateUpdate = CURDATE () WHERE p. dateCreated <'2017-01-01' The table is associated. The price field of the ProductPrice table and the dateUpdate field of the Product table are updated.