Question

是否可以在更新查询中插入from字段？我需要它，因为在更新之前，我需要做一些控制。 p.s我知道我必须使用预备语句，但我想知道这个错误，我想这是一个缺少的引用，我看不到。错误：com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'from warehouse,product where warehouse.idProduct=shop.idProduct and warehouse.id' at line 1

int rs = st.executeUpdate("UPDATE shop SET quantity='"
                        + Quantity
                        + "' from warehouse,product where  
                         warehouse.idProduct=shop.idProduct and 
                         warehouse.idProduct=product.id and product.brand='"
                        + Brand + "' and product.productType='" + Product
                        + "'");

Answer 1

这只是无效的SQL。 UPDATE语句不能包含FROM子句。

Single-table syntax:

UPDATE [LOW_PRIORITY] [IGNORE] table_reference
    SET col_name1={expr1|DEFAULT} [, col_name2={expr2|DEFAULT}] ...
    [WHERE where_condition]
    [ORDER BY ...]
    [LIMIT row_count]

Multiple-table syntax:

UPDATE [LOW_PRIORITY] [IGNORE] table_references
    SET col_name1={expr1|DEFAULT} [, col_name2={expr2|DEFAULT}] ...
    [WHERE where_condition]

Answer 2

我认为你想要一个加入更新：

UPDATE shop s join
       warehouse w
       on w.idProduct = s.idProduct join
       product p
       on w.idProduct = p.id and
          p.productType = '"+Product+"' and
          p.brand = '" + Brand + "'
    SET s.quantity = "+ Quantity

作为一个说明。我猜Quantity是数字。如果是这样，您不需要围绕该值的引号。

更新语法错误

2 个答案: