Question

我有一个非常复杂的SQL查询，如in this fiddle

所示

SELECT payer_payment.payer_id, 
       Sum(payer_payment.amount)                             AS total_paid, 
       Sum(payer_payment.pays * payments_share.single_share) AS fair_share 
FROM   payers 
       INNER JOIN (payer_payment 
                   INNER JOIN (SELECT payment_id, 
                                      Sum(amount) / Sum(pays) AS single_share 
                               FROM   payer_payment 
                               GROUP  BY payment_id) AS payments_share 
                           ON payer_payment.payment_id = 
                              payments_share.payment_id) 
               ON payers.id = payer_payment.payer_id 
WHERE  payers.user_id  = 1 
GROUP  BY payer_payment.payer_id;

在小提琴中，它可以在MySQL上正常运行，但是当我在SQLite数据库上运行它时，它会引发错误，引用：

（1没有这样的栏目：payer_payment.payer_id）

当列清楚存在时。

或简单地返回0结果，具体取决于SQLite实现（WebSQL vs SQLite.js）

这是什么原因，是否可以使我的查询更加数据库不可知？

Answer 1

在SQLite中，您可以使用INTEGER PRIMARY KEY获取自动增量列。（如果你依赖查询中payers.id的实际值，你应该明确地给它们。）

在不需要时，不应尝试嵌套连接：

SELECT payer_payment.payer_id,
       Sum(payer_payment.amount)                             AS total_paid,
       Sum(payer_payment.pays * payments_share.single_share) AS fair_share
FROM       payers
INNER JOIN payer_payment
        ON payers.id = payer_payment.payer_id
INNER JOIN (SELECT payment_id,
                   Sum(amount) / Sum(pays) AS single_share
            FROM   payer_payment
            GROUP  BY payment_id) AS payments_share
        ON payer_payment.payment_id = payments_share.payment_id
WHERE payers.user_id = 1
GROUP BY payer_payment.payer_id;

SQLFiddle

为什么这个查询在SQLite中不起作用，但在MySQL和MSAccess中工作正常？

1 个答案: