mysql.connector.errors.DataError: 1242 (21000): 子查询返回多于 1 行

Question

我有这个代码：

query = """SELECT sp.customer_surname, sp.amount, cp.amount, sp.monthly, sp.date_ FROM set_payment7777 sp JOIN customers_payments7777 cp ON cp.customer_VAT = sp.customer_VAT WHERE sp.date_ = (SELECT MAX(date_) FROM set_payment7777 GROUP BY customer_VAT) GROUP BY sp.customer_VAT"""
mycursor.execute(query)
for row in mycursor:
    #do something

但我得到了错误：

mysql.connector.errors.DataError: 1242 (21000): 子查询返回更多 超过 1 行

Answer 1

您有多个 customer_VAT，然后您的子查询返回不止一行 .. 为避免这种情况，您可以在子查询上使用连接

query = """SELECT sp.customer_surname, sp.amount, cp.amount, sp.monthly, sp.date_ 
    FROM set_payment7777 sp 
    INNER JOIN customers_payments7777 cp ON cp.customer_VAT = sp.customer_VAT 
    INNER JOIN (
        SELECT MAX(date_) FROM set_payment7777 
        GROUP BY customer_VAT
    ) t on t.customer_VAT =  sp.customer_VAT 
    
    GROUP BY sp.customer_VAT"""

无论如何，您有一个没有聚合功能的主选择，那么您应该避免对 group by 的不当使用。在这种情况下，如果您不需要重复结果，请使用 DISTINCT

query = """SELECT DISTINCT sp.customer_surname, sp.amount, cp.amount, sp.monthly, sp.date_ 
    FROM set_payment7777 sp 
    INNER JOIN customers_payments7777 cp ON cp.customer_VAT = sp.customer_VAT 
    INNER JOIN (
        SELECT MAX(date_) FROM set_payment7777 
        GROUP BY customer_VAT
    ) t on t.customer_VAT =  sp.customer_VAT"""