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typemoon
Asked:2024-05-25 02:09:50 +0000 UTC2024-05-25 02:09:50 +0000 UTC

子查询返回错误的行数

  • 772

我的 mysql 查询中发生了一些奇妙的事情。这是我计算成本的查询：

select inv.price_for_one
from invoice inv,
     posinfo pi,
     goods g,
     stock_item si,
     warehouses w
where g.id = :id
  and pi.id = w.pos_info_id
  and si.warehouses_id = w.id
  and g.id = si.goods_id
  and inv.stock_item_id = si.id
  and pi.client_legal_informations_id = 12
  and inv.id = (select max(inv_sub.id)
                from invoice inv_sub,
                     stock_item si_sub
                where inv_sub.id in (inv.id)
                  and inv_sub.warehouses_id = w.id
                  and inv_sub.archive = false
                  and inv_sub.expense = false
                  and inv_sub.stock_item_id = si_sub.id
                  group by inv_sub.id,
                  limit 1);

目前还不清楚为什么它返回两行，但应该只返回一行，这是一个重要的条件。我发现子查询返回两行，因此外部查询也返回两张发票。但是为什么内部查询返回两行呢？

我将真实值插入到子查询中查看它返回的内容，结果如下：

select min(inv_sub.id)
from invoice inv_sub,
     stock_item si_sub
where inv_sub.id in (285, 286)
  and inv_sub.warehouses_id = 623
  and inv_sub.archive = false
  and inv_sub.expense = false
  and inv_sub.stock_item_id = si_sub.id
  group by inv_sub.id,
  limit 1;

这个查询返回了两行。这是怎么回事，这是为什么？

不知怎的，这个建议没有帮助。此查询仍然返回两行，但我们需要最后一张未注销的发票的数据

SELECT inv.price_for_one AS costPriceGoods
            FROM invoice inv,
                 posinfo pi,
                 goods g,
                 stock_item si,
                 warehouses w
            WHERE si.goods_id = g.id
              AND pi.client_legal_informations_id = 12
              AND w.pos_info_id = pi.id
              AND si.warehouses_id = w.id
              AND inv.stock_item_id = si.id
              AND inv.id = (SELECT DISTINCT inv_sub.id
                            FROM invoice inv_sub,
                                 stock_item si_sub
                            WHERE inv_sub.id in (inv.id)
                              AND inv_sub.warehouses_id = w.id
                              AND inv_sub.archive = FALSE
                              AND inv_sub.expense = FALSE
                              AND inv_sub.stock_item_id = si_sub.id
                            ORDER BY inv_sub.id
                            LIMIT 1)
              AND g.id = 10121
            ORDER BY inv.id;

而且内部查询返回一行

SELECT DISTINCT inv_sub.id
                            FROM invoice inv_sub,
                                 stock_item si_sub
                            WHERE inv_sub.id in (287, 288)
                              AND inv_sub.warehouses_id = 205
                              AND inv_sub.archive = FALSE
                              AND inv_sub.expense = FALSE
                              AND inv_sub.stock_item_id = si_sub.id
                            ORDER BY inv_sub.id
                            LIMIT 1
mysql

1 个回答

  1. Best Answer

    让我们从这样一个事实开始：这样的请求根本不会被执行 - LIMIT 1 之前的逗号会干扰您将得到带有 inv_sub.id=285 和 inv_sub.id=286 的行，它们将被分为 2 组和 min 。 (inv_sub.id) 将在其中计算。限制应该保留这2个的第一行（根据MySql），但是这个动作的含义对我来说不是很清楚。您的查询可以转换为：

    select distinct inv_sub.id
from invoice inv_sub,
      stock_item si_sub
where inv_sub.id in (285, 286)
   and inv_sub.warehouses_id = 623
   and inv_sub.archive = false
   and inv_sub.expense = false
   and inv_sub.stock_item_id = si_sub.id
   order by inv_sub.id ASC
   limit 1;

    唯一的问题是哪个会更快

    如果我错了，请纠正我：发票存储在发票表中，我们可以通过请求获取仓库 623 尚未核销的发票列表

    select inv_sub.id 
    from invoice inv_sub 
    where inv_sub.warehouses_id = 623  
      and inv_sub.archive = false  
      and inv_sub.expense = false;

    此列表中的最后一个将是max(inv_sub.id)您需要寻找的。那些。请求必须转换为表格

    SELECT inv.price_for_one AS costPriceGoods
        FROM invoice inv,
             posinfo pi,
             goods g,
             stock_item si,
             warehouses w
        WHERE si.goods_id = g.id
          AND pi.client_legal_informations_id = 12
          AND w.pos_info_id = pi.id
          AND si.warehouses_id = w.id
          AND inv.stock_item_id = si.id
          AND inv.id = (SELECT max(inv_sub.id)
                        FROM invoice inv_sub,
                             stock_item si_sub
                        WHERE inv_sub.warehouses_id = w.id
                          AND inv_sub.archive = FALSE
                          AND inv_sub.expense = FALSE
                          AND inv_sub.stock_item_id = si_sub.id
                        )
          AND g.id = 10121
        ORDER BY inv.id;
    • 2

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