Question

我有以下payment_2015表：

View

我正在检查每个ref_no使用以下查询未支付多少个月：

ref-no  |Jan    |Feb    |Mar   |Apr    |May     |Jun
1       |       |PAID   |PAID  |       |PAID    |  
2       |       |PAID   |      |       |        |PAID
3       |PAID   |       |PAID  |PAID   |PAID    |PAID
4       |PAID   |PAID   |      |PAID   |PAID    |
5       |PAID   |       |PAID  |       |        |
6       |       |       |      |       |        |PAID

结果是以下for(int i = 0; i < all_refNo_list.size(); i++) { qryTxt = "INSERT INTO late_payments " "select ref_no AS ref_no, sum(i_count) as unpaid_count from (" "SELECT ref_no, CASE WHEN January = 'PAID' THEN 0 ELSE 1 END AS i_count, 1 AS month_no FROM payments_" + getCurrentYear() + " UNION SELECT ref_no, CASE WHEN February = 'PAID' THEN 0 ELSE 1 END , 2 FROM payments_" + getCurrentYear() + " UNION SELECT ref_no, CASE WHEN March = 'PAID' THEN 0 ELSE 1 END , 3 FROM payments_" + getCurrentYear() + " UNION SELECT ref_no, CASE WHEN April = 'PAID' THEN 0 ELSE 1 END , 4 FROM payments_" + getCurrentYear() + " UNION SELECT ref_no, CASE WHEN May = 'PAID' THEN 0 ELSE 1 END , 5 FROM payments_" + getCurrentYear() + " UNION SELECT ref_no, CASE WHEN June = 'PAID' THEN 0 ELSE 1 END , 6 FROM payments_" + getCurrentYear() + " UNION SELECT ref_no, CASE WHEN July = 'PAID' THEN 0 ELSE 1 END , 7 FROM payments_" + getCurrentYear() + " UNION SELECT ref_no, CASE WHEN August = 'PAID' THEN 0 ELSE 1 END , 8 FROM payments_" + getCurrentYear() + " UNION SELECT ref_no, CASE WHEN September = 'PAID' THEN 0 ELSE 1 END , 9 FROM payments_" + getCurrentYear() + " UNION SELECT ref_no, CASE WHEN October = 'PAID' THEN 0 ELSE 1 END , 10 FROM payments_" + getCurrentYear() + " UNION SELECT ref_no, CASE WHEN November = 'PAID' THEN 0 ELSE 1 END , 11 FROM payments_" + getCurrentYear() + " UNION SELECT ref_no, CASE WHEN December = 'PAID' THEN 0 ELSE 1 END , 12 FROM payments_" + getCurrentYear() + ") A Where ref_no = " + all_refNo_list[i]; query.prepare(qryTxt); if (!query.exec()) { qDebug() << "Error" << query.lastError().text(); } }表：

late_payments

现在，如果我插入＆＃39; PAID＆＃39;在1月为ref_no = 1，结果仍然相同。当然它会保持不变，因为我正在插入已经存在的记录而不是UPDATing。

每当检查一个月时，我都无法更新这些值，因为付费＆＃39;具体＆＃39; ref_no＆＃39;。即：只要有变化，就更新表格。

更新

我尝试过以下方法：

ref_no   |unpaid_count
1        |3 
2        |4
3        |1
4        |2
5        |4
6        |5

但没有成功..

P.S。：我正在Qt上为c ++应用程序实现这些选择语句。我使用for(int i = 0; i < getAllRefNoList().size(); i++) { qryTxt = "UPDATE late_payments " "SET unpaid_count = (" "select sum(i_count) as unpaid_count from (" "SELECT CASE WHEN January = 'PAID' THEN 0 ELSE 1 END AS i_count, 1 AS month_no FROM payments_" + getCurrentYear() + " UNION SELECT CASE WHEN February = 'PAID' THEN 0 ELSE 1 END , 2 FROM payments_" + getCurrentYear() + " UNION SELECT CASE WHEN March = 'PAID' THEN 0 ELSE 1 END , 3 FROM payments_" + getCurrentYear() + " UNION SELECT CASE WHEN April = 'PAID' THEN 0 ELSE 1 END , 4 FROM payments_" + getCurrentYear() + " UNION SELECT CASE WHEN May = 'PAID' THEN 0 ELSE 1 END , 5 FROM payments_" + getCurrentYear() + " UNION SELECT CASE WHEN June = 'PAID' THEN 0 ELSE 1 END , 6 FROM payments_" + getCurrentYear() + " UNION SELECT CASE WHEN July = 'PAID' THEN 0 ELSE 1 END , 7 FROM payments_" + getCurrentYear() + " UNION SELECT CASE WHEN August = 'PAID' THEN 0 ELSE 1 END , 8 FROM payments_" + getCurrentYear() + " UNION SELECT CASE WHEN September = 'PAID' THEN 0 ELSE 1 END , 9 FROM payments_" + getCurrentYear() + " UNION SELECT CASE WHEN October = 'PAID' THEN 0 ELSE 1 END , 10 FROM payments_" + getCurrentYear() + " UNION SELECT CASE WHEN November = 'PAID' THEN 0 ELSE 1 END , 11 FROM payments_" + getCurrentYear() + " UNION SELECT CASE WHEN December = 'PAID' THEN 0 ELSE 1 END , 12 FROM payments_" + getCurrentYear() + ") A WHERE ref_no = " + getAllRefNoList()[i] + ")"; query.prepare(qryTxt); if (!query.exec()) { qDebug() << "Error" << query.lastError().text(); }在QTableView上显示select语句的结果。

Answer 1

select语句的更新语句为：

UPDATE A
    SET COUNT = <your value>
WHERE ref_no = 1

Answer 2

看起来你这里有两张桌子。一种方法是：

update b
    set count = (select count from a where ref_no = 1);

这将更新b中的所有行。您的问题并未建议将其限制为一行或少量行。

Answer 3

首先，创建一个查询来计算所需的表：

SELECT refno,
       (ifnull(Jan, '') != 'PAID') +
       (ifnull(Feb, '') != 'PAID') +
       ...
       (ifnull(Dec, '') != 'PAID) AS unpaid_count
FROM payments_2015;

然后您可以删除该表，而是使用动态生成这些结果的视图：

CREATE VIEW late_payments_2015 AS
SELECT ...;

SQLITE：如何在UPDATE语句中使用SELECT语句更新表？

3 个答案: