我的子查询不适用于错误消息

【问题标题】：MY subquery does not work with error message我的子查询不适用于错误消息
【发布时间】：2022-01-02 06:09:13
【问题描述】：

当我运行下面显示的查询时，它会给出错误消息。请帮我改正

select Debit_ID,Debit_Date,Debit_Note,Deb_Code,Debit_Amount,Settlement,Debit_Amount-Settlement as Balance
 from

(SELECT id Debit_ID,date Debit_Date ,reference_no Debit_Note ,customer_id Deb_Code,total Debit_Amount,
(select nvl(sum(amount),0) from sma_payments where type='received' and sma_sales.id=sma_payments.sale_id)Settlement
 from sma_sales where customer_id<>1 and sma_sales.sale_status='completed')

[Err] 1064 - 您的 SQL 语法有错误；检查与您的 MariaDB 服务器版本相对应的手册，以获取正确的语法，以便在第 6 行的 '' 附近使用

【问题讨论】：

标签： mysql mariadb

【解决方案1】：

FROM 子句中的子查询需要一个表说明符，即末尾的 AS T：

SELECT
    Debit_ID,
    Debit_Date,
    Debit_Note,
    Deb_Code,
    Debit_Amount,
    Settlement,
    Debit_Amount-Settlement AS Balance 
FROM
    (
    SELECT
        id Debit_ID,
        date Debit_Date,
        reference_no Debit_Note,
        customer_id Deb_Code,
        total Debit_Amount,
        ( SELECT nvl ( sum( amount ), 0 ) FROM sma_payments WHERE type = 'received' AND sma_sales.id = sma_payments.sale_id ) Settlement 
    FROM
        sma_sales 
    WHERE
    customer_id <> 1 
    AND sma_sales.sale_status = 'completed') AS T;

有关更多信息，您可以查阅 MariaDB 文档： https://mariadb.com/kb/en/subqueries-in-a-from-clause/

专业提示：正确格式化 SQL 查询时，调试起来会容易得多。

【讨论】：