Question

SelectionKey key = channel.register(selector, SelectionKey.OP_READ | SelectionKey.OP_WRITE);

对于总存款和未结清总额，我希望它显示＆＃39; 0＆＃39;如果在数据库中为NULL，则显示我尝试使用if else但不工作。

CREATE PROCEDURE dbo.sp_pbos001_list AS

SELECT t1.id
    , t1.customer_code AS cus_code
    , (
        SELECT SUM(transaction_amt - cleared_amt)
        FROM pbosdeposit
        WHERE customer_code = t1.customer_code
        ) AS total_deposit
    , (
        SELECT SUM(inv_amt)
        FROM pbosinvoice
        WHERE customer_code = t1.customer_code
        ) - (
        SELECT SUM(cleared_amt)
        FROM pbosdeposit
        WHERE customer_code = t1.customer_code
        ) AS total_outstanding
FROM customer t1

Answer 1

您可以使用COALESCE替换NULL值：

SELECT t1.id
    , t1.customer_code AS cus_code
    ,COALESCE((
        SELECT SUM(transaction_amt - cleared_amt)
        FROM pbosdeposit
        WHERE customer_code = t1.customer_code
        ),0) AS total_deposit
    , COALESCE((
        SELECT SUM(inv_amt)
        FROM pbosinvoice
        WHERE customer_code = t1.customer_code
        ) - (
        SELECT SUM(cleared_amt)
        FROM pbosdeposit
        WHERE customer_code = t1.customer_code
        ),0) AS total_outstanding
FROM customer t1

Answer 2

使用合并：

            CREATE PROCEDURE dbo.sp_pbos001_list AS

            SELECT t1.id
                , t1.customer_code AS cus_code
                , coalesce((
                    SELECT SUM(transaction_amt - cleared_amt)
                    FROM pbosdeposit
                    WHERE customer_code = t1.customer_code
                    ),0) AS total_deposit
                , coalesce(((
                    SELECT SUM(inv_amt)
                    FROM pbosinvoice
                    WHERE customer_code = t1.customer_code
                    ) - (
                    SELECT SUM(cleared_amt)
                    FROM pbosdeposit
                    WHERE customer_code = t1.customer_code
                    )),0), AS total_outstanding
            FROM customer t1

Answer 3

SQL Server：

manage.py

MySQL的：

ISNULL(total_deposit, 0)

如果数据库存储为Null，如何设置显示0

3 个答案: