Question

我有5张桌子：

    CREATE TABLE Client_master(
    Client_no int(5),
    Client_name varchar(10),
    c_address varchar(10),
    Bdate date,
    PRIMARY KEY(Client_no)
    );

CREATE TABLE Product_master(
    product_no int(5),
    Description varchar(20),
    saleprice int(5),
    costprice int(5),
    PRIMARY KEY(product_no)
    );

CREATE TABLE Sales_master(
    Salesmno int(5),
    Sname varchar(10),
    s_address varchar(5),
    salary float(5),
    Remarks varchar(10),
    PRIMARY KEY(Salesmno)
    );
CREATE TABLE Sales_order(
    order_no int(5),
    Client_no int(5),
    Odate date,
    Delv_add varchar(20),
    Salesmno int(5),
    PRIMARY KEY(order_no),
    FOREIGN KEY(Client_no) REFERENCES Client_master(Client_no),
    FOREIGN KEY(Salesmno) REFERENCES Sales_master(Salesmno)
    );

CREATE TABLE Sales_order_detail(
    order_no int(5),
    product_no int(5),
    qty_order int(5),
    product_rate int(5),
    qty_dispatch int(5),
    FOREIGN KEY(order_no) REFERENCES Sales_order(order_no),
    FOREIGN KEY(product_no) REFERENCES Product_master(product_no)
    );

我必须确定购买超过250美元的客户的名称。我试过这个：

SELECT cm.Client_name, sum(pm.saleprice * sod.product_no)
FROM Sales_order_detail sod 
LEFT JOIN Product_master pm ON sod.product_no = pm.product_no 
LEFT JOIN Sales_order so ON sod.order_no = so.order_no 
LEFT JOIN Client_master cm ON so.Client_no = cm.Client_no 
GROUP BY cm.Client_no WHERE sum(pm.saleprice * sod.product_no) > 250;

但它会出现这样的错误：

您的SQL语法有错误;检查手册对应于您的MySQL服务器版本，以便使用正确的语法 'WHERE sum（pm.saleprice * sod.product_no）＆gt;附近第6行250'

Answer 1

from子句应该在having子句之后，因此您需要在此使用where子句而不是SELECT cm.Client_name, sum(pm.saleprice * sod.product_no) FROM Sales_order_detail sod LEFT JOIN Product_master pm ON sod.product_no = pm.product_no LEFT JOIN Sales_order so ON sod.order_no = so.order_no LEFT JOIN Client_master cm ON so.Client_no = cm.Client_no GROUP BY cm.Client_no having sum(pm.saleprice * sod.product_no) > 250;

a = enumerate('abcdef')
b = enumerate('ghi')

for i, j in zip(a, b):
        print(i, j)
        if i[0] == 0:
            next(itertools.islice(zip(a, b), 1, 1), None)

Answer 2

您的语法错误是由where引起的。但是你不需要left join。您可以将查询编写为：

SELECT cm.Client_name, sum(pm.saleprice * sod.product_no) as total
FROM Sales_order_detail sod JOIN
     Product_master pm
     ON sod.product_no = pm.product_no JOIN
     Sales_order so
     ON sod.order_no = so.order_no JOIN
     Client_master cm
     ON so.Client_no = cm.Client_no 
GROUP BY cm.Client_no 
HAVING total > 250;

请注意，您还可以使用列别名并在HAVING子句中使用它。

购买超过250美元的客户

2 个答案: